C: improve templates

.gitignore

@@ -2,4 +2,7 @@ core
 *.out
 *_test.sh
 test/
+test-framework/
+users/
 .exercism
+.projectile

README.md

@@ -1 +1 @@
-My solutions to some [exercism](https://exercism.io/) exercises.
+My solutions to some [exercism](https://exercism.org/) exercises.

c/allergies/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o tests.out  $(LIBS)

c/allergies/README.md

@@ -0,0 +1,68 @@
+# Allergies
+
+Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.
+
+An allergy test produces a single numeric score which contains the
+information about all the allergies the person has (that they were
+tested for).
+
+The list of items (and their value) that were tested are:
+
+* eggs (1)
+* peanuts (2)
+* shellfish (4)
+* strawberries (8)
+* tomatoes (16)
+* chocolate (32)
+* pollen (64)
+* cats (128)
+
+So if Tom is allergic to peanuts and chocolate, he gets a score of 34.
+
+Now, given just that score of 34, your program should be able to say:
+
+- Whether Tom is allergic to any one of those allergens listed above.
+- All the allergens Tom is allergic to.
+
+Note: a given score may include allergens **not** listed above (i.e.
+allergens that score 256, 512, 1024, etc.).  Your program should
+ignore those components of the score.  For example, if the allergy
+score is 257, your program should only report the eggs (1) allergy.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Jumpstart Lab Warm-up [http://jumpstartlab.com](http://jumpstartlab.com)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/allergies/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/allergies/src/allergies.c

@@ -0,0 +1,20 @@
+#include "allergies.h"
+
+#ifdef USE_ALLERGIC_TO_FUNCTION
+bool is_allergic_to(const allergen_t all, const uint32_t val)
+{
+    return !!(val & (1 << all));
+}
+#endif
+
+allergen_list_t get_allergens(uint32_t val)
+{
+    allergen_list_t list = { .count = 0 };
+    allergen_t i;
+
+    for (i=0; i<ALLERGEN_COUNT; ++i) {
+        list.allergens[i] = is_allergic_to(i, val);
+        list.count += list.allergens[i];
+    }
+    return list;
+}

c/allergies/src/allergies.h

@@ -0,0 +1,46 @@
+#ifndef ALLERGIES_H
+#define ALLERGIES_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef enum {
+   ALLERGEN_EGGS = 0,
+   ALLERGEN_PEANUTS,
+   ALLERGEN_SHELLFISH,
+   ALLERGEN_STRAWBERRIES,
+   ALLERGEN_TOMATOES,
+   ALLERGEN_CHOCOLATE,
+   ALLERGEN_POLLEN,
+   ALLERGEN_CATS,
+   ALLERGEN_COUNT,
+} allergen_t;
+
+typedef struct {
+   int count;
+   bool allergens[ALLERGEN_COUNT];
+} allergen_list_t;
+
+// We can choose macro or function
+#ifdef USE_ALLERGIC_TO_FUNCTION
+bool is_allergic_to(const allergen_t allergen, const uint32_t value);
+#else
+#define is_allergic_to(allerg, val) (!!((val) & (1 << (allerg))))
+#endif
+
+allergen_list_t get_allergens(uint32_t value);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/beer-song/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/beer-song/README.md

@@ -0,0 +1,359 @@
+# Beer Song
+
+Recite the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.
+
+Note that not all verses are identical.
+
+```text
+99 bottles of beer on the wall, 99 bottles of beer.
+Take one down and pass it around, 98 bottles of beer on the wall.
+
+98 bottles of beer on the wall, 98 bottles of beer.
+Take one down and pass it around, 97 bottles of beer on the wall.
+
+97 bottles of beer on the wall, 97 bottles of beer.
+Take one down and pass it around, 96 bottles of beer on the wall.
+
+96 bottles of beer on the wall, 96 bottles of beer.
+Take one down and pass it around, 95 bottles of beer on the wall.
+
+95 bottles of beer on the wall, 95 bottles of beer.
+Take one down and pass it around, 94 bottles of beer on the wall.
+
+94 bottles of beer on the wall, 94 bottles of beer.
+Take one down and pass it around, 93 bottles of beer on the wall.
+
+93 bottles of beer on the wall, 93 bottles of beer.
+Take one down and pass it around, 92 bottles of beer on the wall.
+
+92 bottles of beer on the wall, 92 bottles of beer.
+Take one down and pass it around, 91 bottles of beer on the wall.
+
+91 bottles of beer on the wall, 91 bottles of beer.
+Take one down and pass it around, 90 bottles of beer on the wall.
+
+90 bottles of beer on the wall, 90 bottles of beer.
+Take one down and pass it around, 89 bottles of beer on the wall.
+
+89 bottles of beer on the wall, 89 bottles of beer.
+Take one down and pass it around, 88 bottles of beer on the wall.
+
+88 bottles of beer on the wall, 88 bottles of beer.
+Take one down and pass it around, 87 bottles of beer on the wall.
+
+87 bottles of beer on the wall, 87 bottles of beer.
+Take one down and pass it around, 86 bottles of beer on the wall.
+
+86 bottles of beer on the wall, 86 bottles of beer.
+Take one down and pass it around, 85 bottles of beer on the wall.
+
+85 bottles of beer on the wall, 85 bottles of beer.
+Take one down and pass it around, 84 bottles of beer on the wall.
+
+84 bottles of beer on the wall, 84 bottles of beer.
+Take one down and pass it around, 83 bottles of beer on the wall.
+
+83 bottles of beer on the wall, 83 bottles of beer.
+Take one down and pass it around, 82 bottles of beer on the wall.
+
+82 bottles of beer on the wall, 82 bottles of beer.
+Take one down and pass it around, 81 bottles of beer on the wall.
+
+81 bottles of beer on the wall, 81 bottles of beer.
+Take one down and pass it around, 80 bottles of beer on the wall.
+
+80 bottles of beer on the wall, 80 bottles of beer.
+Take one down and pass it around, 79 bottles of beer on the wall.
+
+79 bottles of beer on the wall, 79 bottles of beer.
+Take one down and pass it around, 78 bottles of beer on the wall.
+
+78 bottles of beer on the wall, 78 bottles of beer.
+Take one down and pass it around, 77 bottles of beer on the wall.
+
+77 bottles of beer on the wall, 77 bottles of beer.
+Take one down and pass it around, 76 bottles of beer on the wall.
+
+76 bottles of beer on the wall, 76 bottles of beer.
+Take one down and pass it around, 75 bottles of beer on the wall.
+
+75 bottles of beer on the wall, 75 bottles of beer.
+Take one down and pass it around, 74 bottles of beer on the wall.
+
+74 bottles of beer on the wall, 74 bottles of beer.
+Take one down and pass it around, 73 bottles of beer on the wall.
+
+73 bottles of beer on the wall, 73 bottles of beer.
+Take one down and pass it around, 72 bottles of beer on the wall.
+
+72 bottles of beer on the wall, 72 bottles of beer.
+Take one down and pass it around, 71 bottles of beer on the wall.
+
+71 bottles of beer on the wall, 71 bottles of beer.
+Take one down and pass it around, 70 bottles of beer on the wall.
+
+70 bottles of beer on the wall, 70 bottles of beer.
+Take one down and pass it around, 69 bottles of beer on the wall.
+
+69 bottles of beer on the wall, 69 bottles of beer.
+Take one down and pass it around, 68 bottles of beer on the wall.
+
+68 bottles of beer on the wall, 68 bottles of beer.
+Take one down and pass it around, 67 bottles of beer on the wall.
+
+67 bottles of beer on the wall, 67 bottles of beer.
+Take one down and pass it around, 66 bottles of beer on the wall.
+
+66 bottles of beer on the wall, 66 bottles of beer.
+Take one down and pass it around, 65 bottles of beer on the wall.
+
+65 bottles of beer on the wall, 65 bottles of beer.
+Take one down and pass it around, 64 bottles of beer on the wall.
+
+64 bottles of beer on the wall, 64 bottles of beer.
+Take one down and pass it around, 63 bottles of beer on the wall.
+
+63 bottles of beer on the wall, 63 bottles of beer.
+Take one down and pass it around, 62 bottles of beer on the wall.
+
+62 bottles of beer on the wall, 62 bottles of beer.
+Take one down and pass it around, 61 bottles of beer on the wall.
+
+61 bottles of beer on the wall, 61 bottles of beer.
+Take one down and pass it around, 60 bottles of beer on the wall.
+
+60 bottles of beer on the wall, 60 bottles of beer.
+Take one down and pass it around, 59 bottles of beer on the wall.
+
+59 bottles of beer on the wall, 59 bottles of beer.
+Take one down and pass it around, 58 bottles of beer on the wall.
+
+58 bottles of beer on the wall, 58 bottles of beer.
+Take one down and pass it around, 57 bottles of beer on the wall.
+
+57 bottles of beer on the wall, 57 bottles of beer.
+Take one down and pass it around, 56 bottles of beer on the wall.
+
+56 bottles of beer on the wall, 56 bottles of beer.
+Take one down and pass it around, 55 bottles of beer on the wall.
+
+55 bottles of beer on the wall, 55 bottles of beer.
+Take one down and pass it around, 54 bottles of beer on the wall.
+
+54 bottles of beer on the wall, 54 bottles of beer.
+Take one down and pass it around, 53 bottles of beer on the wall.
+
+53 bottles of beer on the wall, 53 bottles of beer.
+Take one down and pass it around, 52 bottles of beer on the wall.
+
+52 bottles of beer on the wall, 52 bottles of beer.
+Take one down and pass it around, 51 bottles of beer on the wall.
+
+51 bottles of beer on the wall, 51 bottles of beer.
+Take one down and pass it around, 50 bottles of beer on the wall.
+
+50 bottles of beer on the wall, 50 bottles of beer.
+Take one down and pass it around, 49 bottles of beer on the wall.
+
+49 bottles of beer on the wall, 49 bottles of beer.
+Take one down and pass it around, 48 bottles of beer on the wall.
+
+48 bottles of beer on the wall, 48 bottles of beer.
+Take one down and pass it around, 47 bottles of beer on the wall.
+
+47 bottles of beer on the wall, 47 bottles of beer.
+Take one down and pass it around, 46 bottles of beer on the wall.
+
+46 bottles of beer on the wall, 46 bottles of beer.
+Take one down and pass it around, 45 bottles of beer on the wall.
+
+45 bottles of beer on the wall, 45 bottles of beer.
+Take one down and pass it around, 44 bottles of beer on the wall.
+
+44 bottles of beer on the wall, 44 bottles of beer.
+Take one down and pass it around, 43 bottles of beer on the wall.
+
+43 bottles of beer on the wall, 43 bottles of beer.
+Take one down and pass it around, 42 bottles of beer on the wall.
+
+42 bottles of beer on the wall, 42 bottles of beer.
+Take one down and pass it around, 41 bottles of beer on the wall.
+
+41 bottles of beer on the wall, 41 bottles of beer.
+Take one down and pass it around, 40 bottles of beer on the wall.
+
+40 bottles of beer on the wall, 40 bottles of beer.
+Take one down and pass it around, 39 bottles of beer on the wall.
+
+39 bottles of beer on the wall, 39 bottles of beer.
+Take one down and pass it around, 38 bottles of beer on the wall.
+
+38 bottles of beer on the wall, 38 bottles of beer.
+Take one down and pass it around, 37 bottles of beer on the wall.
+
+37 bottles of beer on the wall, 37 bottles of beer.
+Take one down and pass it around, 36 bottles of beer on the wall.
+
+36 bottles of beer on the wall, 36 bottles of beer.
+Take one down and pass it around, 35 bottles of beer on the wall.
+
+35 bottles of beer on the wall, 35 bottles of beer.
+Take one down and pass it around, 34 bottles of beer on the wall.
+
+34 bottles of beer on the wall, 34 bottles of beer.
+Take one down and pass it around, 33 bottles of beer on the wall.
+
+33 bottles of beer on the wall, 33 bottles of beer.
+Take one down and pass it around, 32 bottles of beer on the wall.
+
+32 bottles of beer on the wall, 32 bottles of beer.
+Take one down and pass it around, 31 bottles of beer on the wall.
+
+31 bottles of beer on the wall, 31 bottles of beer.
+Take one down and pass it around, 30 bottles of beer on the wall.
+
+30 bottles of beer on the wall, 30 bottles of beer.
+Take one down and pass it around, 29 bottles of beer on the wall.
+
+29 bottles of beer on the wall, 29 bottles of beer.
+Take one down and pass it around, 28 bottles of beer on the wall.
+
+28 bottles of beer on the wall, 28 bottles of beer.
+Take one down and pass it around, 27 bottles of beer on the wall.
+
+27 bottles of beer on the wall, 27 bottles of beer.
+Take one down and pass it around, 26 bottles of beer on the wall.
+
+26 bottles of beer on the wall, 26 bottles of beer.
+Take one down and pass it around, 25 bottles of beer on the wall.
+
+25 bottles of beer on the wall, 25 bottles of beer.
+Take one down and pass it around, 24 bottles of beer on the wall.
+
+24 bottles of beer on the wall, 24 bottles of beer.
+Take one down and pass it around, 23 bottles of beer on the wall.
+
+23 bottles of beer on the wall, 23 bottles of beer.
+Take one down and pass it around, 22 bottles of beer on the wall.
+
+22 bottles of beer on the wall, 22 bottles of beer.
+Take one down and pass it around, 21 bottles of beer on the wall.
+
+21 bottles of beer on the wall, 21 bottles of beer.
+Take one down and pass it around, 20 bottles of beer on the wall.
+
+20 bottles of beer on the wall, 20 bottles of beer.
+Take one down and pass it around, 19 bottles of beer on the wall.
+
+19 bottles of beer on the wall, 19 bottles of beer.
+Take one down and pass it around, 18 bottles of beer on the wall.
+
+18 bottles of beer on the wall, 18 bottles of beer.
+Take one down and pass it around, 17 bottles of beer on the wall.
+
+17 bottles of beer on the wall, 17 bottles of beer.
+Take one down and pass it around, 16 bottles of beer on the wall.
+
+16 bottles of beer on the wall, 16 bottles of beer.
+Take one down and pass it around, 15 bottles of beer on the wall.
+
+15 bottles of beer on the wall, 15 bottles of beer.
+Take one down and pass it around, 14 bottles of beer on the wall.
+
+14 bottles of beer on the wall, 14 bottles of beer.
+Take one down and pass it around, 13 bottles of beer on the wall.
+
+13 bottles of beer on the wall, 13 bottles of beer.
+Take one down and pass it around, 12 bottles of beer on the wall.
+
+12 bottles of beer on the wall, 12 bottles of beer.
+Take one down and pass it around, 11 bottles of beer on the wall.
+
+11 bottles of beer on the wall, 11 bottles of beer.
+Take one down and pass it around, 10 bottles of beer on the wall.
+
+10 bottles of beer on the wall, 10 bottles of beer.
+Take one down and pass it around, 9 bottles of beer on the wall.
+
+9 bottles of beer on the wall, 9 bottles of beer.
+Take one down and pass it around, 8 bottles of beer on the wall.
+
+8 bottles of beer on the wall, 8 bottles of beer.
+Take one down and pass it around, 7 bottles of beer on the wall.
+
+7 bottles of beer on the wall, 7 bottles of beer.
+Take one down and pass it around, 6 bottles of beer on the wall.
+
+6 bottles of beer on the wall, 6 bottles of beer.
+Take one down and pass it around, 5 bottles of beer on the wall.
+
+5 bottles of beer on the wall, 5 bottles of beer.
+Take one down and pass it around, 4 bottles of beer on the wall.
+
+4 bottles of beer on the wall, 4 bottles of beer.
+Take one down and pass it around, 3 bottles of beer on the wall.
+
+3 bottles of beer on the wall, 3 bottles of beer.
+Take one down and pass it around, 2 bottles of beer on the wall.
+
+2 bottles of beer on the wall, 2 bottles of beer.
+Take one down and pass it around, 1 bottle of beer on the wall.
+
+1 bottle of beer on the wall, 1 bottle of beer.
+Take it down and pass it around, no more bottles of beer on the wall.
+
+No more bottles of beer on the wall, no more bottles of beer.
+Go to the store and buy some more, 99 bottles of beer on the wall.
+```
+
+## For bonus points
+
+Did you get the tests passing and the code clean? If you want to, these
+are some additional things you could try:
+
+* Remove as much duplication as you possibly can.
+* Optimize for readability, even if it means introducing duplication.
+* If you've removed all the duplication, do you have a lot of
+  conditionals? Try replacing the conditionals with polymorphism, if it
+  applies in this language. How readable is it?
+
+Then please share your thoughts in a comment on the submission. Did this
+experiment make the code better? Worse? Did you learn anything from it?
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Learn to Program by Chris Pine [http://pine.fm/LearnToProgram/?Chapter=06](http://pine.fm/LearnToProgram/?Chapter=06)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/beer-song/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/beer-song/src/beer_song.c

@@ -0,0 +1,44 @@
+#include "beer_song.h"
+#include <stdio.h>
+
+static char *fmt1="%s bottle%s of beer on the wall, %s bottle%s of beer.\n" \
+    "Take %s down and pass it around, %s bottle%s of beer on the wall.\n%s";
+static char *fmt2="%s bottle%s of beer on the wall, %s bottle%s of beer.\n" \
+    "%sGo to the store and buy some more, %s bottle%s of beer on the wall.\n%s";
+
+void recite(unsigned int start, unsigned int down, char *buffer)
+{
+    char n1[16], n2[16];
+    char *p=buffer;
+
+    while (down--) {
+        sprintf(n1, "%d", start);
+        sprintf(n2, "%d", start>1? start-1: 99);
+
+        p+=sprintf(p, start? fmt1: fmt2,
+                   start? n1: "No more", start==1? "": "s", start? n1: "no more",
+                   start==1? "": "s",
+                   start==1? "it": start? "one": "", start-1? n2: "no more",
+                   start==2? "": "s", down? "\n": "");
+        start=start? start-1: 99;
+    }
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    unsigned i, j;
+    char buffer[1024];
+
+    for (; arg<ac-1; ++arg, ++arg) {
+        i=atoi(av[arg]);
+        j=atoi(av[arg+1]);
+        recite(i, j, buffer);
+        printf("recite(%d, %d):\n%s", i, j, buffer);
+    }
+}
+#endif

c/beer-song/src/beer_song.h

@@ -0,0 +1,18 @@
+#ifndef BEER_SONG_H
+#define BEER_SONG_H
+
+void recite(unsigned int start_bottles, unsigned int take_down, char *buffer);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/binary-search/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/binary-search/README.md

@@ -0,0 +1,73 @@
+# Binary Search
+
+Implement a binary search algorithm.
+
+Searching a sorted collection is a common task. A dictionary is a sorted
+list of word definitions. Given a word, one can find its definition. A
+telephone book is a sorted list of people's names, addresses, and
+telephone numbers. Knowing someone's name allows one to quickly find
+their telephone number and address.
+
+If the list to be searched contains more than a few items (a dozen, say)
+a binary search will require far fewer comparisons than a linear search,
+but it imposes the requirement that the list be sorted.
+
+In computer science, a binary search or half-interval search algorithm
+finds the position of a specified input value (the search "key") within
+an array sorted by key value.
+
+In each step, the algorithm compares the search key value with the key
+value of the middle element of the array.
+
+If the keys match, then a matching element has been found and its index,
+or position, is returned.
+
+Otherwise, if the search key is less than the middle element's key, then
+the algorithm repeats its action on the sub-array to the left of the
+middle element or, if the search key is greater, on the sub-array to the
+right.
+
+If the remaining array to be searched is empty, then the key cannot be
+found in the array and a special "not found" indication is returned.
+
+A binary search halves the number of items to check with each iteration,
+so locating an item (or determining its absence) takes logarithmic time.
+A binary search is a dichotomic divide and conquer search algorithm.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Wikipedia [http://en.wikipedia.org/wiki/Binary_search_algorithm](http://en.wikipedia.org/wiki/Binary_search_algorithm)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/binary-search/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/binary-search/src/binary_search.c

@@ -0,0 +1,37 @@
+#include "binary_search.h"
+
+const int *binary_search(int v, const int *a, size_t size)
+{
+    size_t lo, hi, i;
+
+    /* early exclude invalid/trivial result: NULL/empty array, value off bounds
+     */
+    if (!size || !a || v < *a || v > *(a+size-1))
+        return NULL;
+    for (lo=0, hi=size-1, i=hi/2; lo<hi && a[i]!=v; i=lo+(hi-lo)/2) {
+        if (a[i] < v)
+            lo=i+1;
+        else
+            hi=i-1;
+    }
+    return a[i]==v? a+i: NULL;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1, *res;
+    int i, array[] = {1, 2, 3, 4, 6, 7, 8, 9 };
+    size_t size = sizeof(array) / sizeof(array[0]);
+
+    for (; arg<ac; ++arg) {
+        i=atoi(av[arg]);
+        res=binary_search(i, array, size);
+        printf("binary_search(%d)=%ld\n", i,
+               res? res-array: -1);
+    }
+}
+#endif

c/binary-search/src/binary_search.h

@@ -0,0 +1,21 @@
+#ifndef BINARY_SEARCH_H
+#define BINARY_SEARCH_H
+
+#include <stddef.h>
+
+const int *binary_search(int value, const int *arr, size_t length);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/bob/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/bob/README.md

@@ -0,0 +1,54 @@
+# Bob
+
+Bob is a lackadaisical teenager. In conversation, his responses are very limited.
+
+Bob answers 'Sure.' if you ask him a question, such as "How are you?".
+
+He answers 'Whoa, chill out!' if you YELL AT HIM (in all capitals).
+
+He answers 'Calm down, I know what I'm doing!' if you yell a question at him.
+
+He says 'Fine. Be that way!' if you address him without actually saying
+anything.
+
+He answers 'Whatever.' to anything else.
+
+Bob's conversational partner is a purist when it comes to written communication and always follows normal rules regarding sentence punctuation in English.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Inspired by the 'Deaf Grandma' exercise in Chris Pine's Learn to Program tutorial. [http://pine.fm/LearnToProgram/?Chapter=06](http://pine.fm/LearnToProgram/?Chapter=06)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/bob/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/bob/src/bob.c

@@ -0,0 +1,40 @@
+#include <ctype.h>
+#include "bob.h"
+
+char*answers[] = {
+    "Whatever.",
+    "Sure.",
+    "Whoa, chill out!",
+    "Calm down, I know what I'm doing!",
+    "Fine. Be that way!"
+};
+
+char *hey_bob(char *w)
+{
+    int yell=2, question=0, empty=4, text=0;
+    for (;*w; w++) {
+        if (!isspace(*w)) {
+            empty=0;
+            if (isalpha(*w))  text=2;
+            if (islower (*w)) yell=0;
+            question=*w=='?'? 1: 0;
+        }
+    }
+    return answers[(text&yell)|question|empty];
+}
+
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+#include <stdio.h>
+int main(int ac, char **av)
+{
+    int arg=1;
+
+    for (; arg<ac; ++arg) {
+        printf("bob(%s)=%s\n", av[arg], hey_bob(av[arg]));
+    }
+}
+#endif

c/bob/src/bob.h

@@ -0,0 +1,18 @@
+#ifndef BOB_H
+#define BOB_H
+
+char *hey_bob(char *greeting);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/circular-buffer/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o tests.out  $(LIBS)

c/circular-buffer/README.md

@@ -0,0 +1,89 @@
+# Circular Buffer
+
+A circular buffer, cyclic buffer or ring buffer is a data structure that
+uses a single, fixed-size buffer as if it were connected end-to-end.
+
+A circular buffer first starts empty and of some predefined length. For
+example, this is a 7-element buffer:
+
+    [ ][ ][ ][ ][ ][ ][ ]
+
+Assume that a 1 is written into the middle of the buffer (exact starting
+location does not matter in a circular buffer):
+
+    [ ][ ][ ][1][ ][ ][ ]
+
+Then assume that two more elements are added — 2 & 3 — which get
+appended after the 1:
+
+    [ ][ ][ ][1][2][3][ ]
+
+If two elements are then removed from the buffer, the oldest values
+inside the buffer are removed. The two elements removed, in this case,
+are 1 & 2, leaving the buffer with just a 3:
+
+    [ ][ ][ ][ ][ ][3][ ]
+
+If the buffer has 7 elements then it is completely full:
+
+    [6][7][8][9][3][4][5]
+
+When the buffer is full an error will be raised, alerting the client
+that further writes are blocked until a slot becomes free.
+
+When the buffer is full, the client can opt to overwrite the oldest
+data with a forced write. In this case, two more elements — A & B —
+are added and they overwrite the 3 & 4:
+
+    [6][7][8][9][A][B][5]
+
+3 & 4 have been replaced by A & B making 5 now the oldest data in the
+buffer. Finally, if two elements are removed then what would be
+returned is 5 & 6 yielding the buffer:
+
+    [ ][7][8][9][A][B][ ]
+
+Because there is space available, if the client again uses overwrite
+to store C & D then the space where 5 & 6 were stored previously will
+be used not the location of 7 & 8. 7 is still the oldest element and
+the buffer is once again full.
+
+    [D][7][8][9][A][B][C]
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Wikipedia [http://en.wikipedia.org/wiki/Circular_buffer](http://en.wikipedia.org/wiki/Circular_buffer)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/circular-buffer/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/circular-buffer/src/circular_buffer.c

@@ -0,0 +1,75 @@
+#include <malloc.h>
+#include <errno.h>
+
+#include "circular_buffer.h"
+
+#define INC(v, size) {if (++v==size) v=0;}
+
+circular_buffer_t *new_circular_buffer(size_t size)
+{
+    circular_buffer_t *head = NULL;
+
+    if (size > 0) {
+        if ((head=malloc(sizeof(*head)))) {
+            clear_buffer(head);
+            head->size = size;
+            /* we could have only 1 alloc, I just prefer this double alloc
+             */
+            if (!(head->buf  = calloc(size, sizeof(buffer_value_t)))) {
+                free(head);
+                head = NULL;
+            }
+        }
+    }
+    return head;
+}
+
+int do_write(circular_buffer_t *b, buffer_value_t v, int f)
+{
+    if (!f  && b->used == b->size) {
+        errno = ENOBUFS;
+        return EXIT_FAILURE;
+    }
+    b->buf[b->head] = v;
+    INC(b->head, b->size);
+    if (f && b->used == b->size)                  /* overwrite and full */
+        INC(b->tail, b->size);
+    if (b->used < b->size)                        /* normal write */
+        b->used++;
+    return EXIT_SUCCESS;
+}
+
+int read(circular_buffer_t *b, buffer_value_t *p)
+{
+    if (!b->used) {
+        errno = ENODATA;
+        return EXIT_FAILURE;
+    }
+    b->used--;
+    *p = b->buf[b->tail];
+    INC(b->tail, b->size);
+    return EXIT_SUCCESS;
+}
+
+int clear_buffer(circular_buffer_t *b)
+{
+    b->head = 0;
+    b->tail = 0;
+    b->used = 0;
+    return EXIT_SUCCESS;
+}
+
+void delete_buffer(circular_buffer_t *b) {
+    free(b->buf);
+    free(b);
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    /* not done for circular buffer : simple exercise, with difficult testing */
+}
+#endif

c/circular-buffer/src/circular_buffer.h

@@ -0,0 +1,41 @@
+#ifndef CIRCULAR_BUFFER_H
+#define CIRCULAR_BUFFER_H
+
+#include <stdlib.h>
+
+typedef char buffer_value_t;
+
+/* used and tail are redundant, but allow easier code (and maybe easier
+ * to read ?).
+ */
+typedef struct circular_buffer {
+    int head;
+    int tail;
+    int used;
+    int size;
+    buffer_value_t *buf;
+} circular_buffer_t;
+
+extern circular_buffer_t *new_circular_buffer(size_t size);
+extern int do_write(circular_buffer_t *buffer, buffer_value_t value, int force);
+extern int read(circular_buffer_t *buffer, buffer_value_t *retval);
+extern int clear_buffer(circular_buffer_t *buffer);
+extern void delete_buffer(circular_buffer_t *buffer);
+
+#define write(buffer, value)     do_write((buffer), (value), 0)
+#define overwrite(buffer, value) do_write((buffer), (value), 1)
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/complex-numbers/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/complex-numbers/README.md

@@ -0,0 +1,67 @@
+# Complex Numbers
+
+A complex number is a number in the form `a + b * i` where `a` and `b` are real and `i` satisfies `i^2 = -1`.
+
+`a` is called the real part and `b` is called the imaginary part of `z`.
+The conjugate of the number `a + b * i` is the number `a - b * i`.
+The absolute value of a complex number `z = a + b * i` is a real number `|z| = sqrt(a^2 + b^2)`. The square of the absolute value `|z|^2` is the result of multiplication of `z` by its complex conjugate.
+
+The sum/difference of two complex numbers involves adding/subtracting their real and imaginary parts separately:
+`(a + i * b) + (c + i * d) = (a + c) + (b + d) * i`,
+`(a + i * b) - (c + i * d) = (a - c) + (b - d) * i`.
+
+Multiplication result is by definition
+`(a + i * b) * (c + i * d) = (a * c - b * d) + (b * c + a * d) * i`.
+
+The reciprocal of a non-zero complex number is
+`1 / (a + i * b) = a/(a^2 + b^2) - b/(a^2 + b^2) * i`.
+
+Dividing a complex number `a + i * b` by another `c + i * d` gives:
+`(a + i * b) / (c + i * d) = (a * c + b * d)/(c^2 + d^2) + (b * c - a * d)/(c^2 + d^2) * i`.
+
+Raising e to a complex exponent can be expressed as `e^(a + i * b) = e^a * e^(i * b)`, the last term of which is given by Euler's formula `e^(i * b) = cos(b) + i * sin(b)`.
+
+Implement the following operations:
+ - addition, subtraction, multiplication and division of two complex numbers,
+ - conjugate, absolute value, exponent of a given complex number.
+
+
+Assume the programming language you are using does not have an implementation of complex numbers.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Wikipedia [https://en.wikipedia.org/wiki/Complex_number](https://en.wikipedia.org/wiki/Complex_number)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/complex-numbers/makefile

@@ -0,0 +1,38 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+CFLAGS += -DUNITY_INCLUDE_DOUBLE
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/complex-numbers/src/complex_numbers.c

@@ -0,0 +1,96 @@
+#include "complex_numbers.h"
+
+#ifdef USE_COMPLEX_FUNCTIONS
+
+complex_t c_add(complex_t a, complex_t b)
+{
+    return (complex_t) {
+        .real = a.real+b.real,
+        .imag = a.imag+b.imag
+    };
+}
+
+complex_t c_sub(complex_t a, complex_t b)
+{
+    return (complex_t) {
+        .real = a.real-b.real,
+        .imag = a.imag-b.imag
+    };
+}
+
+complex_t c_mul(complex_t a, complex_t b)
+{
+    return (complex_t) {
+        .real = a.real*b.real - a.imag*b.imag,
+        .imag = a.imag*b.real + a.real*b.imag,
+    };
+}
+
+complex_t c_div(complex_t a, complex_t b)
+{
+    double d = b.real*b.real + b.imag*b.imag;
+    return (complex_t) {
+        .real = (a.real*b.real + a.imag*b.imag)/d,
+        .imag = (a.imag*b.real - a.real*b.imag)/d
+    };
+}
+
+double c_abs(complex_t x)
+{
+    return sqrt(x.real*x.real + x.imag*x.imag);
+}
+
+complex_t c_conjugate(complex_t x)
+{
+    return (complex_t) {
+        .real = x.real,
+        .imag = -x.imag
+    };
+}
+
+double c_real(complex_t x)
+{
+    return x.real;
+}
+
+double c_imag(complex_t x)
+{
+    return x.imag;
+}
+
+complex_t c_exp(complex_t x)
+{
+    return (complex_t) {
+        .real = exp(x.real)*cos(x.imag),
+        .imag = exp(x.real)*sin(x.imag)
+    };
+}
+
+#endif
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int ac, char **av)
+{
+    int arg=1;
+    complex_t c1, c2, c3;
+
+    for (; arg<ac-3; ++arg, ++arg) {
+        c1.real=atof(av[arg]);
+        c1.imag=atof(av[arg+1]);
+
+        c2.real=atof(av[arg+2]);
+        c2.imag=atof(av[arg+3]);
+        c3 = c_add(c1, c2);
+        printf("(%f + %fi) + (%f + %fi) = (%f + %fi)\n",
+               c1.real, c1.imag,
+               c2.real, c2.imag,
+               c3.real, c3.imag);
+    }
+}
+#endif

c/complex-numbers/src/complex_numbers.h

@@ -0,0 +1,70 @@
+#ifndef _COMPLEX_NUMBERS_H_
+#define _COMPLEX_NUMBERS_H_
+#include <math.h>
+
+typedef struct {
+   double real;
+   double imag;
+} complex_t;
+
+/* default is to use macros */
+#ifdef USE_COMPLEX_FUNCTIONS
+
+complex_t c_add(complex_t a, complex_t b);
+complex_t c_sub(complex_t a, complex_t b);
+complex_t c_mul(complex_t a, complex_t b);
+complex_t c_div(complex_t a, complex_t b);
+double c_abs(complex_t x);
+complex_t c_conjugate(complex_t x);
+double c_real(complex_t x);
+double c_imag(complex_t x);
+complex_t c_exp(complex_t x);
+
+#else
+
+#define c_add(a,b) (complex_t) {                      \
+        (a).real+(b).real,                            \
+        (a).imag+(b).imag }
+
+#define c_sub(a,b) (complex_t) {                      \
+        (a).real-(b).real,                            \
+        (a).imag-(b).imag }
+
+#define c_mul(a,b) (complex_t) {                      \
+        (a).real*(b).real - (a).imag*(b).imag,        \
+        (a).imag*(b).real + (a).real*(b).imag }
+
+#define c_div(a,b) (complex_t) {                      \
+        ((a).real*(b).real + (a).imag*(b).imag)/      \
+            ((b).real*(b).real + (b).imag*(b).imag),  \
+        ((a).imag*(b).real - (a).real*(b).imag)/      \
+            ((b).real*(b).real + (b).imag*(b).imag) }
+
+#define c_exp(x) (complex_t) {                        \
+        exp((x).real) * cos((x).imag),                \
+        exp((x).real) * sin((x).imag) }
+
+#define c_abs(x) { sqrt((x).real*(x).real + (x).imag*(x).imag) }
+
+#define c_conjugate(x) (complex_t){ (x).real, -(x).imag }
+
+#define c_real(x) (x).real
+
+#define c_imag(x) (x).imag
+
+
+#endif
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/grade-school/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/grade-school/README.md

@@ -0,0 +1,76 @@
+# Grade School
+
+Given students' names along with the grade that they are in, create a roster
+for the school.
+
+In the end, you should be able to:
+
+- Add a student's name to the roster for a grade
+  - "Add Jim to grade 2."
+  - "OK."
+- Get a list of all students enrolled in a grade
+  - "Which students are in grade 2?"
+  - "We've only got Jim just now."
+- Get a sorted list of all students in all grades.  Grades should sort
+  as 1, 2, 3, etc., and students within a grade should be sorted
+  alphabetically by name.
+  - "Who all is enrolled in school right now?"
+  - "Let me think. We have
+  Anna, Barb, and Charlie in grade 1,
+  Alex, Peter, and Zoe in grade 2
+  and Jim in grade 5.
+  So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe and Jim"
+
+Note that all our students only have one name.  (It's a small town, what
+do you want?)
+
+## For bonus points
+
+Did you get the tests passing and the code clean? If you want to, these
+are some additional things you could try:
+
+- If you're working in a language with mutable data structures and your
+  implementation allows outside code to mutate the school's internal DB
+  directly, see if you can prevent this. Feel free to introduce additional
+  tests.
+
+Then please share your thoughts in a comment on the submission. Did this
+experiment make the code better? Worse? Did you learn anything from it?
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+A pairing session with Phil Battos at gSchool [http://gschool.it](http://gschool.it)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/grade-school/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/grade-school/src/grade_school.c

@@ -0,0 +1,83 @@
+#include "grade_school.h"
+#include <string.h>
+#include <stdio.h>
+
+#define STD(i) roster.students[i]
+#define NAME(i) roster.students[i].name
+#define GRADE(i) roster.students[i].grade
+
+static roster_t roster;
+
+void clear_roster()
+{
+    roster.count=0;
+}
+
+/* testing program expects bool here, but I prefer to return students count,
+ * it makes more sense for me.
+ */
+int add_student(const char *s, const uint8_t g)
+{
+    int c=roster.count, i;
+
+    if (c >= MAX_STUDENTS)
+        return 0;
+    // find correct place to insert name
+    for (i=0; i<c && (GRADE(i)<g || (GRADE(i)==g && strcmp(s, NAME(i))>0)); ++i)
+        ;
+    for (int j=c-1; j>=i; --j)                    /* move rest to right */
+        STD(j+1)=STD(j);
+    NAME(i)=s;                                    /* insert new name */
+    GRADE(i)=g;
+
+    return ++roster.count;
+}
+
+/* to avoid this everytime, we could build up one roster per grade while
+ * adding students, but really overkill here.
+ */
+roster_t get_grade(const uint8_t g)
+{
+    roster_t r;
+    unsigned i, j;
+
+    for (i=0, j=0; i<roster.count && GRADE(i)<=g; ++i) {
+        if (GRADE(i)==g)
+            r.students[j++]=STD(i);
+    }
+    r.count=j;
+
+    return r;
+}
+
+roster_t get_roster()
+{
+    return roster;
+}
+
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+static void print_roster()
+{
+    unsigned i;
+    printf("======== roster size: %lu\n", roster.count);
+    for (i=0; i<roster.count; ++i)
+        printf("roster(%02d): [%d]%s\n", i, GRADE(i), NAME(i));
+    printf("\n");
+}
+
+int main(int ac, char **av)
+{
+    int arg=1;
+    uint8_t i;
+
+    for (; arg<ac-1; ++arg, ++arg) {
+        i=atoi(av[arg]);
+        add_student(av[arg+1], i);
+    }
+    print_roster();
+}
+#endif

c/grade-school/src/grade_school.h

@@ -0,0 +1,36 @@
+#ifndef GRADE_SCHOOL_H
+#define GRADE_SCHOOL_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define MAX_STUDENTS    20
+
+typedef struct student_s {
+    uint8_t grade;
+    const char *name;
+} student_t;
+
+typedef struct {
+    size_t count;
+    student_t students[MAX_STUDENTS];
+} roster_t;
+
+void clear_roster(void);
+int add_student(const char *student, const uint8_t grade);
+roster_t get_grade(const uint8_t grade);
+roster_t get_roster(void);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/hamming/src/hamming.c

@@ -1,14 +1,5 @@
 #include "hamming.h"
 
-/* Note: For explanation on section below, see 'GNUfilename' included in
- * link below :
- * https://exercism.io/my/solutions/103b2f7d92db42309c1988030f5202c7
- */
-#if defined UNIT_TEST || defined DEBUG
-#include <stdio.h>
-#include <stdlib.h>
-#endif
-
 /* test does not include invalid input, but it should, as the subject is
  * about DNA sequence, not ASCII chars sequence :-)
  * exercism test needs only:
@@ -16,22 +7,25 @@
  */
 #define V(p) (*(p)=='A' || *(p)=='C' || *(p)=='G' || *(p)=='T')
 
-int compute(const char *lhs, const char *rhs)
+int compute(const char *l, const char *r)
 {
     int res=0;
-    const char *l=lhs, *r=rhs;
 
     if (!l || !r)
         return -1;
-    for (; V(l) && V(r); ++l, ++r) {
+    for (; V(l) && V(r); ++l, ++r)
         if (*l != *r)
             res++;
-    }
-    return *r || *l? -1: res;
+    return *l || *r? -1: res;
 }
 
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST
+#include <stdio.h>
+#include <stdlib.h>
 
-#ifdef UNIT_TEST
 int main(int ac, char **av)
 {
     if (ac==3) {

c/hamming/src/hamming.h

@@ -3,9 +3,8 @@
 
 int compute(const char *lhs, const char *rhs);
 
-/* Note: For explanation on section below, see 'GNUfilename' included in
- * link below :
- * https://exercism.io/my/solutions/103b2f7d92db42309c1988030f5202c7
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
  */
 #ifdef  TESTALL
 #undef  TEST_IGNORE

c/leap/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/leap/README.md

@@ -0,0 +1,62 @@
+# Leap
+
+Given a year, report if it is a leap year.
+
+The tricky thing here is that a leap year in the Gregorian calendar occurs:
+
+```text
+on every year that is evenly divisible by 4
+  except every year that is evenly divisible by 100
+    unless the year is also evenly divisible by 400
+```
+
+For example, 1997 is not a leap year, but 1996 is.  1900 is not a leap
+year, but 2000 is.
+
+## Notes
+
+Though our exercise adopts some very simple rules, there is more to
+learn!
+
+For a delightful, four minute explanation of the whole leap year
+phenomenon, go watch [this youtube video][video].
+
+[video]: http://www.youtube.com/watch?v=xX96xng7sAE
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+JavaRanch Cattle Drive, exercise 3 [http://www.javaranch.com/leap.jsp](http://www.javaranch.com/leap.jsp)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/leap/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/leap/src/leap.c

@@ -0,0 +1,24 @@
+#include "leap.h"
+
+/* already dont in meetup exercise */
+bool leap_year(int y)
+{
+    return ((y % 4) ||
+            (y % 400 && !(y % 100)))? false: true;
+}
+
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1, i;
+
+    for (; arg<ac; ++arg) {
+        i=atoi(av[arg]);
+        printf("leap_year(%d)=%d\n", i, leap_year(i));
+    }
+}
+#endif

c/leap/src/leap.h

@@ -0,0 +1,20 @@
+#ifndef LEAP_H
+#define LEAP_H
+
+#include <stdbool.h>
+
+bool leap_year(int year);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/linked-list/GNUmakefile

@@ -0,0 +1,56 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+# 1) copy it into exercise directory
+# 2) add ex.h to exercise include file
+# 3) add ex.c to exercise source code, and create a suitable main function
+# 4) use make with one of the following targets :
+#   all: compile and run all predefined tests.
+#   nowarn: compile with no -Werror, and run all predefined tests
+#   debug: compile with -DDEBUG and run all predefined tests
+#   mem: perform memcheck with all tests enabled
+#   unit: build standalone (unit) bimary
+#   unitnowarn: build standalone (unit) binary with -Werror disabled
+#   unitdebug: build standalone binary with -DDEBUG
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all nowarn debug mem unit unitnowarn unitdebug standalone
+
+default: all
+
+ALLSOURCES:=$(wildcard ./*.c)
+TESTSOURCES:=$(wildcard ./test_*.c)
+SRC:=$(filter-out $(TESTSOURCES),$(ALLSOURCES))
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+nowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+nowarn: clean all
+
+debug: CFLAGS+=-DDEBUG
+debug: all
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unitnowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+unitnowarn: clean unit
+
+unitdebug: CFLAGS+=-DDEBUG
+unitdebug: clean unit
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: *.c *.h
+	$(CC) $(CFLAGS) $(SRC) -o tests.out  $(LIBS)

c/linked-list/HELP.md

@@ -0,0 +1,63 @@
+# Help
+
+## Running the tests
+
+Get the first test compiling, linking and passing by following the [three rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test` task.
+
+```console
+$ make test
+```
+
+Create just the functions you need to satisfy any compiler errors and get the test to fail.
+Then write just enough code to get the test to pass.
+Once you've done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your implementation for readability and expressiveness and then go on to the next test.
+
+Try to use standard C99 facilities in preference to writing your own low-level algorithms or facilities by hand.
+
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit linked_list.c linked_list.h` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [C track's documentation](https://exercism.org/docs/tracks/c)
+- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+Make sure you have read the "Guides" section of the [C track][c-track] on the Exercism site.
+This covers the basic information on setting up the development environment expected by the exercises.
+
+## Submitting Incomplete Solutions
+
+If you are struggling with a particular exercise, it is possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+## Resources
+
+To get help if having trouble, you can use the following resources:
+
+- [StackOverflow][] can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.
+- [CPPReference][] can be used to look up information on C concepts, operators, types, standard library functions and more.
+- [TutorialsPoint][] has similar content as CPPReference in its C programming section.
+- [The C Programming][K&R] book by K&R is the original source of the language and is still useful today.
+
+[c-track]: https://exercism.io/my/tracks/c
+[stackoverflow]: http://stackoverflow.com/questions/tagged/c
+[cppreference]: https://en.cppreference.com/w/c
+[tutorialspoint]: https://www.tutorialspoint.com/cprogramming/
+[K&R]: https://www.amazon.com/Programming-Language-2nd-Brian-Kernighan/dp/0131103628/

c/linked-list/README.md

@@ -0,0 +1,50 @@
+# Linked List
+
+Welcome to Linked List on Exercism's C Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Implement a doubly linked list.
+
+Like an array, a linked list is a simple linear data structure. Several
+common data types can be implemented using linked lists, like queues,
+stacks, and associative arrays.
+
+A linked list is a collection of data elements called *nodes*. In a
+*singly linked list* each node holds a value and a link to the next node.
+In a *doubly linked list* each node also holds a link to the previous
+node.
+
+You will write an implementation of a doubly linked list. Implement a
+Node to hold a value and pointers to the next and previous nodes. Then
+implement a List which holds references to the first and last node and
+offers an array-like interface for adding and removing items:
+
+* `push` (*insert value at back*);
+* `pop` (*remove value at back*);
+* `shift` (*remove value at front*).
+* `unshift` (*insert value at front*);
+
+To keep your implementation simple, the tests will not cover error
+conditions. Specifically: `pop` or `shift` will never be called on an
+empty list.
+
+If you want to know more about linked lists, check [Wikipedia](https://en.wikipedia.org/wiki/Linked_list).
+
+## Source
+
+### Created by
+
+- @wolf99
+
+### Contributed to by
+
+- @patricksjackson
+- @QLaille
+- @ryanplusplus
+- @siebenschlaefer
+
+### Based on
+
+Classic computer science topic

c/linked-list/br-common.h

@@ -0,0 +1,45 @@
+#ifndef __BR_COMMON_H
+#define __BR_COMMON_H
+
+/* ${LINUX_SRC}/include/linux/compiler_attributes.h, around line 30
+ *
+ * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17.
+ * For other compilers, simple implementation (for __falltrough__ only)
+ */
+#ifndef __has_attribute
+#  define __has_attribute(x) __GCC4_has_attribute_##x
+#  define __GCC4_has_attribute___assume_aligned__      (__GNUC_MINOR__ >= 9)
+#  define __GCC4_has_attribute___copy__                0
+#  define __GCC4_has_attribute___designated_init__     0
+#  define __GCC4_has_attribute___externally_visible__  1
+#  define __GCC4_has_attribute___no_caller_saved_registers__ 0
+#  define __GCC4_has_attribute___noclone__             1
+#  define __GCC4_has_attribute___nonstring__           0
+#  define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
+#  define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9)
+#  define __GCC4_has_attribute___fallthrough__         0
+#  define __GCC4_has_attribute___fallthrough__         0
+#endif
+
+/* ${LINUX_SRC}/include/linux/compiler_attributes.h, around line 200
+ */
+#if __has_attribute(__fallthrough__)
+#  define fallthrough                    __attribute__((__fallthrough__))
+#else
+#  define fallthrough                    do {} while (0)  /* fallthrough */
+#endif
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#  include <stdio.h>
+#  include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#  undef  TEST_IGNORE
+#  define TEST_IGNORE() {}
+#endif
+
+#endif  /* __BR_COMMON_H */

c/linked-list/linked_list.c

@@ -0,0 +1,138 @@
+#include <malloc.h>
+
+#include "list.h"
+#include "linked_list.h"
+
+/* How it works :
+ *
+ * The usual way to use linked lists is to have a list_head whith
+ * 'next' pointing to first node, and 'prev' pointing to last node.
+ * Each node has also 'prev' and 'next' pointers.
+ *
+ * Here, list_head points to  the node own list_head structure,
+ * and each node list_head points to next/previous node list_head.
+ *
+ * Advantage: We don't need to manipulate the pointers, all lists
+ * use the same code, independently of the object (node) structure.
+ */
+struct list_node {
+    ll_data_t data;
+    struct list_head list;
+};
+
+/* duplicate of list_head struct
+ */
+struct list {
+    struct list_head *next, *prev;
+};
+
+/* constructs a new (empty) list
+ */
+struct list *list_create()
+{
+    struct list_head *list;
+
+    if (!(list=malloc(sizeof (*list))))
+        return NULL;
+    INIT_LIST_HEAD(list);
+    return (struct list *) list;
+}
+
+/* counts the items on a list
+ */
+size_t list_count(const struct list *list_head)
+{
+    size_t len = 0;
+    struct list_head *p;
+
+    list_for_each(p, (struct list_head *)list_head)
+        len++;
+    return len;
+}
+
+/* inserts item at back of a list
+ */
+void list_push(const struct list *list, const ll_data_t item_data)
+{
+    struct list_node *p;
+
+    if ((p=malloc(sizeof(*p)))) {
+        p->data = item_data;
+        list_add_tail(&p->list, (struct list_head*)list);
+    }
+}
+
+/* deletes an element
+ */
+static ll_data_t _list_del(const struct list_head *list)
+{
+    struct list_node *node;
+    ll_data_t data;
+
+    node = list_entry(list, struct list_node, list);
+    data = node->data;
+    list_del(&node->list);
+    free(node);
+    return data;
+}
+
+/* removes item from back of a list
+ */
+ll_data_t list_pop(const struct list *list)
+{
+    return list_empty((struct list_head*)list) ? -1 : _list_del(list->prev);
+}
+
+/* inserts item at front of a list
+ */
+void list_unshift(const struct list *list, const ll_data_t item_data)
+{
+    struct list_node *p;
+
+    if ((p=malloc(sizeof(*p)))) {
+        p->data = item_data;
+        list_add(&p->list, (struct list_head*)list);
+    }
+}
+
+/* removes item from front of a list
+ */
+ll_data_t list_shift(const struct list *list)
+{
+    return list_empty((struct list_head*)list) ? -1 : _list_del(list->next);
+}
+
+/* finds a element that matches data
+ */
+static struct list_node *_node_find(const struct list *list, const ll_data_t data)
+{
+    struct list_node *p;
+
+    list_for_each_entry(p, (struct list_head *)list, list) {
+        if (p->data == data)
+            return p;
+    }
+    return NULL;
+}
+
+/* deletes a node that holds the matching data
+ */
+void list_delete(const struct list *list, const ll_data_t data)
+{
+    struct list_node *p;
+
+    if ((p = _node_find(list, data)))
+        _list_del(&p->list);
+}
+
+/* destroys an entire list
+ * list will be a dangling pointer after calling this method on it
+ */
+void list_destroy(struct list *list)
+{
+    struct list_head *cur, *tmp;
+
+    list_for_each_safe(cur, tmp, (struct list_head *)list)
+        _list_del(cur);
+    free(list);
+}

c/linked-list/linked_list.h

@@ -0,0 +1,36 @@
+#ifndef LINKED_LIST_H
+#define LINKED_LIST_H
+
+#include <stddef.h>
+
+typedef int ll_data_t;
+struct list;
+
+// constructs a new (empty) list
+struct list *list_create(void);
+
+// counts the items on a list
+size_t list_count(const struct list *list);
+
+// inserts item at back of a list
+void list_push(const struct list *list, const ll_data_t item_data);
+
+// removes item from back of a list
+ll_data_t list_pop(const struct list *list);
+
+// inserts item at front of a list
+void list_unshift(const struct list *list, const ll_data_t item_data);
+
+// removes item from front of a list
+ll_data_t list_shift(const struct list *list);
+
+// deletes a node that holds the matching data
+void list_delete(const struct list *list, const ll_data_t data);
+
+// destroys an entire list
+// list will be a dangling pointer after calling this method on it
+void list_destroy(struct list *list);
+
+#endif
+
+#include "br-common.h"

c/linked-list/list.h

@@ -0,0 +1,229 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* stripped down version of my adaptation of Linux kernel lists management :
+ *    https://github.com/braoult/Tools/blob/master/C/list.h
+ */
+#ifndef __LIST_H
+#define __LIST_H
+
+#include <stddef.h>
+#include <stdbool.h>
+
+/************ originally in <include/linux/types.h> */
+struct list_head {
+    struct list_head *next, *prev;
+};
+
+/************ originally in <include/linux/poison.h> */
+#define LIST_POISON1  ((void *) 0x100)
+#define LIST_POISON2  ((void *) 0x122)
+
+/************ originally in <include/linux/kernel.h> */
+#define container_of(ptr, type, member) \
+    ((type *)((char *)(ptr) - offsetof(type, member)))
+
+/*
+ * Circular doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
+ */
+
+/**
+ * INIT_LIST_HEAD - Initialize a list_head structure
+ * @list: list_head structure to be initialized.
+ *
+ * Initializes the list_head to point to itself.  If it is a list header,
+ * the result is an empty list.
+ */
+static inline void INIT_LIST_HEAD(struct list_head *list)
+{
+    list->next = list;
+    list->prev = list;
+}
+
+/*
+ * Insert a new entry between two known consecutive entries.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_add(struct list_head *new,
+			      struct list_head *prev,
+			      struct list_head *next)
+{
+    next->prev = new;
+    new->next  = next;
+    new->prev  = prev;
+    prev->next = new;
+}
+
+/**
+ * list_add - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it after
+ *
+ * Insert a new entry after the specified head.
+ * This is good for implementing stacks.
+ */
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+    __list_add(new, head, head->next);
+}
+
+
+/**
+ * list_add_tail - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head.
+ * This is useful for implementing queues.
+ */
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{
+    __list_add(new, head->prev, head);
+}
+
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_del(struct list_head * prev, struct list_head * next)
+{
+    next->prev = prev;
+    prev->next = next;
+}
+
+static inline void __list_del_entry(struct list_head *entry)
+{
+    __list_del(entry->prev, entry->next);
+}
+
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty() on entry does not return true after this, the entry is
+ * in an undefined state.
+ */
+static inline void list_del(struct list_head *entry)
+{
+    __list_del_entry(entry);
+    entry->next = LIST_POISON1;
+    entry->prev = LIST_POISON2;
+}
+
+/**
+ * list_empty - tests whether a list is empty
+ * @head: the list to test.
+ */
+static inline int list_empty(const struct list_head *head)
+{
+    return head->next == head;
+}
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr:	the &struct list_head pointer.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry(ptr, type, member)           \
+    container_of(ptr, type, member)
+
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member)     \
+    list_entry((ptr)->next, type, member)
+
+/**
+ * list_last_entry - get the last element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member)      \
+    list_entry((ptr)->prev, type, member)
+
+/**
+ * list_next_entry - get the next element in list
+ * @pos:	the type * to cursor
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_next_entry(pos, member)                            \
+    list_entry((pos)->member.next, __typeof__(*(pos)), member)
+
+/**
+ * list_prev_entry - get the prev element in list
+ * @pos:	the type * to cursor
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_prev_entry(pos, member)                            \
+    list_entry((pos)->member.prev, __typeof__(*(pos)), member)
+
+/**
+ * list_for_each	-	iterate over a list
+ * @pos:	the &struct list_head to use as a loop cursor.
+ * @head:	the head for your list.
+ */
+#define list_for_each(pos, head)                                \
+    for (pos = (head)->next; pos != (head); pos = pos->next)
+
+/**
+ * list_for_each_safe - iterate over a list safe against removal of list entry
+ * @pos:	the &struct list_head to use as a loop cursor.
+ * @n:		another &struct list_head to use as temporary storage
+ * @head:	the head for your list.
+ */
+#define list_for_each_safe(pos, n, head)                        \
+    for (pos = (head)->next, n = pos->next; pos != (head);      \
+         pos = n, n = pos->next)
+
+/**
+ * list_entry_is_head - test if the entry points to the head of the list
+ * @pos:	the type * to cursor
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry_is_head(pos, head, member)   \
+    (&pos->member == (head))
+
+/**
+ * list_for_each_entry	-	iterate over list of given type
+ * @pos:	the type * to use as a loop cursor.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry(pos, head, member)                  \
+    for (pos = list_first_entry(head, __typeof__(*pos), member);	\
+         !list_entry_is_head(pos, head, member);                \
+         pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member)          \
+    for (pos = list_first_entry(head, __typeof__(*pos), member),	\
+             n = list_next_entry(pos, member);			\
+         !list_entry_is_head(pos, head, member);                \
+         pos = n, n = list_next_entry(n, member))
+
+#endif /* __LIST_H */

c/linked-list/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: ./*.c ./*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) test-framework/unity.c ./*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: ./*.c ./*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) test-framework/unity.c ./*.c -o tests.out $(LIBS)

c/linked-list/test_linked_list.c

@@ -0,0 +1,243 @@
+#include <stddef.h>
+#include "test-framework/unity.h"
+#include "linked_list.h"
+
+struct list *list = NULL;
+
+void setUp(void)
+{
+   list = list_create();
+}
+
+void tearDown(void)
+{
+   if (list) {
+      list_destroy(list);
+      list = NULL;
+   }
+}
+
+static void test_pop_gets_element_from_the_list(void)
+{
+   list_push(list, 7);
+   TEST_ASSERT_EQUAL(7, list_pop(list));
+}
+
+static void test_push_pop_respectively_add_remove_at_the_end_of_the_list(void)
+{
+   TEST_IGNORE();               // delete this line to run test
+   list_push(list, 11);
+   list_push(list, 13);
+   TEST_ASSERT_EQUAL(13, list_pop(list));
+   TEST_ASSERT_EQUAL(11, list_pop(list));
+}
+
+static void test_shift_gets_an_element_from_the_list(void)
+{
+   TEST_IGNORE();
+   list_push(list, 17);
+   TEST_ASSERT_EQUAL(17, list_shift(list));
+}
+
+static void test_shift_gets_first_element_from_the_list(void)
+{
+   TEST_IGNORE();
+   list_push(list, 23);
+   list_push(list, 5);
+   TEST_ASSERT_EQUAL(23, list_shift(list));
+   TEST_ASSERT_EQUAL(5, list_shift(list));
+}
+
+static void test_unshift_adds_element_at_start_of_the_list(void)
+{
+   TEST_IGNORE();
+   list_unshift(list, 23);
+   list_unshift(list, 5);
+   TEST_ASSERT_EQUAL(5, list_shift(list));
+   TEST_ASSERT_EQUAL(23, list_shift(list));
+}
+
+static void test_pop_push_shift_and_unshift_can_be_used_in_any_order(void)
+{
+   TEST_IGNORE();
+   list_push(list, 1);
+   list_push(list, 2);
+   TEST_ASSERT_EQUAL(2, list_pop(list));
+   list_push(list, 3);
+   TEST_ASSERT_EQUAL(1, list_shift(list));
+   list_unshift(list, 4);
+   list_push(list, 5);
+   TEST_ASSERT_EQUAL(4, list_shift(list));
+   TEST_ASSERT_EQUAL(5, list_pop(list));
+   TEST_ASSERT_EQUAL(3, list_shift(list));
+}
+
+static void test_count_an_empty_list(void)
+{
+   TEST_IGNORE();
+   TEST_ASSERT_EQUAL(0, list_count(list));
+}
+
+static void test_count_a_list_with_items(void)
+{
+   TEST_IGNORE();
+   list_push(list, 37);
+   list_push(list, 1);
+   TEST_ASSERT_EQUAL(2, list_count(list));
+}
+
+static void test_count_is_correct_after_mutation(void)
+{
+   TEST_IGNORE();
+   list_push(list, 31);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   list_unshift(list, 43);
+   TEST_ASSERT_EQUAL(2, list_count(list));
+   list_shift(list);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   list_pop(list);
+   TEST_ASSERT_EQUAL(0, list_count(list));
+}
+
+static void test_popping_to_empty_does_not_break_the_list(void)
+{
+   TEST_IGNORE();
+   list_push(list, 41);
+   list_push(list, 59);
+   list_pop(list);
+   list_pop(list);
+   list_push(list, 47);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   TEST_ASSERT_EQUAL(47, list_pop(list));
+}
+
+static void test_shifting_to_empty_does_not_break_the_list(void)
+{
+   TEST_IGNORE();
+   list_push(list, 41);
+   list_push(list, 59);
+   list_shift(list);
+   list_shift(list);
+   list_push(list, 47);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   TEST_ASSERT_EQUAL(47, list_shift(list));
+}
+
+static void test_deletes_the_only_element(void)
+{
+   TEST_IGNORE();
+   list_push(list, 61);
+   list_delete(list, 61);
+   TEST_ASSERT_EQUAL(0, list_count(list));
+}
+
+static void
+test_deletes_the_element_with_the_specified_value_from_the_list(void)
+{
+   TEST_IGNORE();
+   list_push(list, 71);
+   list_push(list, 83);
+   list_push(list, 79);
+   list_delete(list, 83);
+   TEST_ASSERT_EQUAL(2, list_count(list));
+   TEST_ASSERT_EQUAL(79, list_pop(list));
+   TEST_ASSERT_EQUAL(71, list_shift(list));
+}
+
+static void
+ test_deletes_the_element_with_the_specified_value_from_the_list_reassigns_tail
+    (void) {
+   TEST_IGNORE();
+   list_push(list, 71);
+   list_push(list, 83);
+   list_push(list, 79);
+   list_delete(list, 83);
+   TEST_ASSERT_EQUAL(2, list_count(list));
+   TEST_ASSERT_EQUAL(79, list_pop(list));
+   TEST_ASSERT_EQUAL(71, list_pop(list));
+}
+
+static void
+ test_deletes_the_element_with_the_specified_value_from_the_list_reassigns_head
+    (void) {
+   TEST_IGNORE();
+   list_push(list, 71);
+   list_push(list, 83);
+   list_push(list, 79);
+   list_delete(list, 83);
+   TEST_ASSERT_EQUAL(2, list_count(list));
+   TEST_ASSERT_EQUAL(71, list_shift(list));
+   TEST_ASSERT_EQUAL(79, list_shift(list));
+}
+
+static void test_deletes_the_first_of_two_elements(void)
+{
+   TEST_IGNORE();
+   list_push(list, 97);
+   list_push(list, 101);
+   list_delete(list, 97);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   TEST_ASSERT_EQUAL(101, list_pop(list));
+}
+
+static void test_deletes_the_second_of_two_elements(void)
+{
+   TEST_IGNORE();
+   list_push(list, 97);
+   list_push(list, 101);
+   list_delete(list, 101);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+   TEST_ASSERT_EQUAL(97, list_pop(list));
+}
+
+static void
+test_delete_does_not_modify_the_list_if_the_element_is_not_found(void)
+{
+   TEST_IGNORE();
+   list_push(list, 89);
+   list_delete(list, 103);
+   TEST_ASSERT_EQUAL(1, list_count(list));
+}
+
+static void test_deletes_only_the_first_occurrence(void)
+{
+   TEST_IGNORE();
+   list_push(list, 73);
+   list_push(list, 9);
+   list_push(list, 9);
+   list_push(list, 107);
+   list_delete(list, 9);
+   TEST_ASSERT_EQUAL(3, list_count(list));
+   TEST_ASSERT_EQUAL(107, list_pop(list));
+   TEST_ASSERT_EQUAL(9, list_pop(list));
+   TEST_ASSERT_EQUAL(73, list_pop(list));
+}
+
+int main(void)
+{
+   UnityBegin("test_linked_list.c");
+
+   RUN_TEST(test_pop_gets_element_from_the_list);
+   RUN_TEST(test_push_pop_respectively_add_remove_at_the_end_of_the_list);
+   RUN_TEST(test_shift_gets_an_element_from_the_list);
+   RUN_TEST(test_shift_gets_first_element_from_the_list);
+   RUN_TEST(test_unshift_adds_element_at_start_of_the_list);
+   RUN_TEST(test_pop_push_shift_and_unshift_can_be_used_in_any_order);
+   RUN_TEST(test_count_an_empty_list);
+   RUN_TEST(test_count_a_list_with_items);
+   RUN_TEST(test_count_is_correct_after_mutation);
+   RUN_TEST(test_popping_to_empty_does_not_break_the_list);
+   RUN_TEST(test_shifting_to_empty_does_not_break_the_list);
+   RUN_TEST(test_deletes_the_only_element);
+   RUN_TEST(test_deletes_the_element_with_the_specified_value_from_the_list);
+   RUN_TEST
+       (test_deletes_the_element_with_the_specified_value_from_the_list_reassigns_tail);
+   RUN_TEST
+       (test_deletes_the_element_with_the_specified_value_from_the_list_reassigns_head);
+   RUN_TEST(test_deletes_the_first_of_two_elements);
+   RUN_TEST(test_deletes_the_second_of_two_elements);
+   RUN_TEST(test_delete_does_not_modify_the_list_if_the_element_is_not_found);
+   RUN_TEST(test_deletes_only_the_first_occurrence);
+
+   return UnityEnd();
+}

c/list-ops/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o tests.out  $(LIBS)

c/list-ops/README.md

@@ -0,0 +1,54 @@
+# List Ops
+
+Implement basic list operations.
+
+In functional languages list operations like `length`, `map`, and
+`reduce` are very common. Implement a series of basic list operations,
+without using existing functions.
+
+The precise number and names of the operations to be implemented will be
+track dependent to avoid conflicts with existing names, but the general
+operations you will implement include:
+
+* `append` (*given two lists, add all items in the second list to the end of the first list*);
+* `concatenate` (*given a series of lists, combine all items in all lists into one flattened list*);
+* `filter` (*given a predicate and a list, return the list of all items for which `predicate(item)` is True*);
+* `length` (*given a list, return the total number of items within it*);
+* `map` (*given a function and a list, return the list of the results of applying `function(item)` on all items*);
+* `foldl` (*given a function, a list, and initial accumulator, fold (reduce) each item into the accumulator from the left using `function(accumulator, item)`*);
+* `foldr` (*given a function, a list, and an initial accumulator, fold (reduce) each item into the accumulator from the right using `function(item, accumulator)`*);
+* `reverse` (*given a list, return a list with all the original items, but in reversed order*);
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/list-ops/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/list-ops/src/list_ops.c

@@ -0,0 +1,136 @@
+#include <malloc.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "list_ops.h"
+
+list_t *new_list(size_t len, list_element_t elts[])
+{
+    list_t *list;
+
+    if (len > MAX_LIST_LENGTH ||
+        !(list=malloc(sizeof(list_t) + len*sizeof(list_element_t))))
+        return NULL;
+    list->length = len;
+    if (elts)
+        memcpy(list->elements, elts, len * sizeof(list_element_t));
+    return list;
+}
+
+list_t *append_list(list_t *l1, list_t *l2)
+{
+    list_t *l;
+    size_t len=l1->length+l2->length;
+
+    if (!(l=new_list(len, NULL)))
+        return NULL;
+    memcpy(l->elements, l1->elements, l1->length * sizeof(list_element_t));
+    memcpy(l->elements + l1->length, l2->elements,
+           l2->length * sizeof(list_element_t));
+    l->length=len;
+    return l;
+}
+
+list_t *filter_list(list_t * l, bool(*f) (list_element_t))
+{
+    size_t p1, p2;
+    list_t *list=new_list(l->length, NULL);
+
+    if (list) {
+        for (p1=0, p2=0; p1 < l->length; ++p1) {
+            if (f(l->elements[p1]))
+                list->elements[p2++]=l->elements[p1];
+        }
+    }
+    list->length=p2;
+    return list;
+}
+
+/* I don't like this function return value, and more generally using size_t
+ * as list length.
+ */
+size_t length_list(list_t *l)
+{
+    return l? l->length: INVALID_LENGTH;
+}
+
+list_t *map_list(list_t * l, list_element_t(*map) (list_element_t))
+{
+    size_t i;
+    list_t *list=new_list(l->length, NULL);
+
+    if (list) {
+        for (i=0; i < l->length; ++i)
+            list->elements[i] = map(l->elements[i]);
+    }
+    return list;
+}
+
+list_element_t foldl_list(list_t * l, list_element_t init,
+                          list_element_t(*f) (list_element_t, list_element_t))
+{
+    size_t i;
+
+    for (i = 0; i < l->length; ++i)
+        init = f(l->elements[i], init);
+    return init;
+}
+
+list_element_t foldr_list(list_t * l, list_element_t init,
+                          list_element_t(*f) (list_element_t, list_element_t))
+{
+    ptrdiff_t i;
+
+    for (i = l->length-1; i >= 0; --i)
+        init = f(l->elements[i], init);
+    return init;
+}
+
+list_t *reverse_list(list_t * l)
+{
+    size_t i;
+    list_t *list=new_list(l->length, NULL);
+
+    if (list) {
+        for (i=0; i < l->length; ++i)
+            list->elements[l->length-i-1] = l->elements[i];
+    }
+    return list;
+}
+
+void delete_list(list_t * l)
+{
+    free(l);
+}
+
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+static void print_list(list_t *l)
+{
+    printf("list (%lu) = ", l->length);
+    for (size_t i=0; i<l->length; ++i)
+        printf("%d ", l->elements[i]);
+    printf("\n");
+}
+
+int main(int ac, char **av)
+{
+    int arg=1, i;
+    list_t *l1=new_list(0, NULL);
+    list_t *l2, *l3;
+
+    for (; arg<ac; ++arg) {
+        i=atoi(av[arg]);
+        l2 = new_list(1, (list_element_t[]){ i });
+        l3 = append_list(l1, l2);
+        delete_list(l2);
+        delete_list(l1);
+        l1=l3;
+    }
+    print_list(l1);
+    delete_list(l1);
+}
+#endif

c/list-ops/src/list_ops.h

@@ -0,0 +1,62 @@
+#ifndef LINKED_LIST_H
+#define LINKED_LIST_H
+
+#include <stdlib.h>
+#include <stdbool.h>
+
+typedef char list_element_t;
+typedef struct {
+   size_t length;
+   list_element_t elements[];
+} list_t;
+
+#define MAX_LIST_LENGTH 1024
+#define INVALID_LENGTH  (size_t)-1
+
+// constructs a new list
+extern list_t *new_list(size_t length, list_element_t elements[]);
+
+// append entries to a list and return the new list
+extern list_t *append_list(list_t * list1, list_t * list2);
+
+// filter list returning only values that satisfy the filter function
+extern list_t *filter_list(list_t * list, bool(*filter) (list_element_t));
+
+// returns the length of the list
+extern size_t length_list(list_t * list);
+
+// return a list of elements whose values equal the list value transformed by
+// the mapping function
+extern list_t *map_list(list_t * list, list_element_t(*map) (list_element_t));
+
+// folds (reduces) the given list from the left with a function
+extern list_element_t foldl_list(list_t * list, list_element_t initial,
+                                 list_element_t(*foldl) (list_element_t,
+                                                         list_element_t));
+
+// folds (reduces) the given list from the right with a function
+extern list_element_t foldr_list(list_t * list, list_element_t initial,
+                                 list_element_t(*foldr) (list_element_t,
+                                                         list_element_t));
+
+// reverse the elements of the list
+extern list_t *reverse_list(list_t * list);
+
+// destroy the entire list
+// list will be a dangling pointer after calling this method on it
+extern void delete_list(list_t * list);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/nucleotide-count/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/nucleotide-count/README.md

@@ -0,0 +1,59 @@
+# Nucleotide Count
+
+Each of us inherits from our biological parents a set of chemical instructions known as DNA that influence how our bodies are constructed. All known life depends on DNA!
+
+> Note: You do not need to understand anything about nucleotides or DNA to complete this exercise.
+
+DNA is a long chain of other chemicals and the most important are the four nucleotides, adenine, cytosine, guanine and thymine. A single DNA chain can contain billions of these four nucleotides and the order in which they occur is important!
+We call the order of these nucleotides in a bit of DNA a "DNA sequence".
+
+We represent a DNA sequence as an ordered collection of these four nucleotides and a common way to do that is with a string of characters such as "ATTACG" for a DNA sequence of 6 nucleotides.
+'A' for adenine, 'C' for cytosine, 'G' for guanine, and 'T' for thymine.
+
+Given a string representing a DNA sequence, count how many of each nucleotide is present.
+If the string contains characters that aren't A, C, G, or T then it is invalid and you should signal an error.
+
+For example:
+
+```
+"GATTACA" -> 'A': 3, 'C': 1, 'G': 1, 'T': 2
+"INVALID" -> error
+```
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+The Calculating DNA Nucleotides_problem at Rosalind [http://rosalind.info/problems/dna/](http://rosalind.info/problems/dna/)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/nucleotide-count/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/nucleotide-count/src/nucleotide_count.c

@@ -0,0 +1,68 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include "nucleotide_count.h"
+
+typedef unsigned char uchar;
+
+static int C[256] = {
+    ['A']=1, ['C']=2, ['G']=3, ['T']=4
+};
+
+/* not in C99: we implement asprintf */
+static char *asprintf(const char *fmt, ...)
+{
+    int n = 0;
+    char *p = NULL;
+    va_list ap;
+
+    va_start(ap, fmt);
+    n = vsnprintf(p, 0, fmt, ap);
+    va_end(ap);
+
+    if (n < 0 || !(p=malloc(n+1)))
+        return NULL;
+
+    va_start(ap, fmt);
+    n = vsnprintf(p, n+1, fmt, ap);
+    va_end(ap);
+    if (n < 0) {
+        free(p);
+        return NULL;
+    }
+
+    return p;
+}
+
+char *count(const char *dna)
+{
+    int res[4]={ 0 };
+
+    if (!dna)
+        return NULL;                              /* should it be "" ? */
+
+    for (const uchar *p=(uchar *)dna; *p; ++p) {
+        if (!C[*p])
+            return asprintf("");
+        res[C[*p]-1]++;
+    }
+    return asprintf("A:%d C:%d G:%d T:%d", res[0], res[1], res[2], res[3]);
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    char *p;
+
+    //printf("%s: %s\n", asprintf("%d %d %d %d %s", (long)av-(long)av, ac, arg, 1000, "foobar"));
+    for (; arg<ac; ++arg) {
+        p=count(av[arg]);
+        printf("%s: [%s] len=%lu\n", av[arg], p, strlen(p));
+    }
+}
+#endif

c/nucleotide-count/src/nucleotide_count.h

@@ -0,0 +1,18 @@
+#ifndef _NUCLEOTIDE_COUNT_H
+#define _NUCLEOTIDE_COUNT_H
+
+char *count(const char *dna_strand);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/phone-number/GNUmakefile

@@ -0,0 +1,56 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+# 1) copy it into exercise directory
+# 2) add ex.h to exercise include file
+# 3) add ex.c to exercise source code, and create a suitable main function
+# 4) use make with one of the following targets :
+#   all: compile and run all predefined tests.
+#   nowarn: compile with no -Werror, and run all predefined tests
+#   debug: compile with -DDEBUG and run all predefined tests
+#   mem: perform memcheck with all tests enabled
+#   unit: build standalone (unit) bimary
+#   unitnowarn: build standalone (unit) binary with -Werror disabled
+#   unitdebug: build standalone binary with -DDEBUG
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all nowarn debug mem unit unitnowarn unitdebug standalone
+
+default: all
+
+ALLSOURCES:=$(wildcard ./*.c)
+TESTSOURCES:=$(wildcard ./test_*.c)
+SRC:=$(filter-out $(TESTSOURCES),$(ALLSOURCES))
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+nowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+nowarn: clean all
+
+debug: CFLAGS+=-DDEBUG
+debug: all
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unitnowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+unitnowarn: clean unit
+
+unitdebug: CFLAGS+=-DDEBUG
+unitdebug: clean unit
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: *.c *.h
+	$(CC) $(CFLAGS) $(SRC) -o tests.out  $(LIBS)

c/phone-number/HELP.md

@@ -0,0 +1,63 @@
+# Help
+
+## Running the tests
+
+Get the first test compiling, linking and passing by following the [three rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test` task.
+
+```console
+$ make test
+```
+
+Create just the functions you need to satisfy any compiler errors and get the test to fail.
+Then write just enough code to get the test to pass.
+Once you've done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your implementation for readability and expressiveness and then go on to the next test.
+
+Try to use standard C99 facilities in preference to writing your own low-level algorithms or facilities by hand.
+
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit phone_number.c phone_number.h` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [C track's documentation](https://exercism.org/docs/tracks/c)
+- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+Make sure you have read the "Guides" section of the [C track][c-track] on the Exercism site.
+This covers the basic information on setting up the development environment expected by the exercises.
+
+## Submitting Incomplete Solutions
+
+If you are struggling with a particular exercise, it is possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+## Resources
+
+To get help if having trouble, you can use the following resources:
+
+- [StackOverflow][] can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.
+- [CPPReference][] can be used to look up information on C concepts, operators, types, standard library functions and more.
+- [TutorialsPoint][] has similar content as CPPReference in its C programming section.
+- [The C Programming][K&R] book by K&R is the original source of the language and is still useful today.
+
+[c-track]: https://exercism.io/my/tracks/c
+[stackoverflow]: http://stackoverflow.com/questions/tagged/c
+[cppreference]: https://en.cppreference.com/w/c
+[tutorialspoint]: https://www.tutorialspoint.com/cprogramming/
+[K&R]: https://www.amazon.com/Programming-Language-2nd-Brian-Kernighan/dp/0131103628/

c/phone-number/README.md

@@ -0,0 +1,56 @@
+# Phone Number
+
+Welcome to Phone Number on Exercism's C Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Clean up user-entered phone numbers so that they can be sent SMS messages.
+
+The **North American Numbering Plan (NANP)** is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: `1`.
+
+NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as *area code*, followed by a seven-digit local number. The first three digits of the local number represent the *exchange code*, followed by the unique four-digit number which is the *subscriber number*.
+
+The format is usually represented as
+
+```text
+(NXX)-NXX-XXXX
+```
+
+where `N` is any digit from 2 through 9 and `X` is any digit from 0 through 9.
+
+Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.
+
+For example, the inputs
+- `+1 (613)-995-0253`
+- `613-995-0253`
+- `1 613 995 0253`
+- `613.995.0253`
+
+should all produce the output
+
+`6139950253`
+
+**Note:** As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.
+
+## Source
+
+### Created by
+
+- @RealBarrettBrown
+
+### Contributed to by
+
+- @bcc32
+- @Gamecock
+- @gea-migration
+- @h-3-0
+- @mikewalker
+- @patricksjackson
+- @QLaille
+- @ryanplusplus
+- @wolf99
+
+### Based on
+
+Event Manager by JumpstartLab - http://tutorials.jumpstartlab.com/projects/eventmanager.html

c/phone-number/br-common.h

@@ -0,0 +1,45 @@
+#ifndef __BR_COMMON_H
+#define __BR_COMMON_H
+
+/* ${LINUX_SRC}/include/linux/compiler_attributes.h, around line 30
+ *
+ * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17.
+ * For other compilers, simple implementation (for __falltrough__ only)
+ */
+#ifndef __has_attribute
+#  define __has_attribute(x) __GCC4_has_attribute_##x
+#  define __GCC4_has_attribute___assume_aligned__      (__GNUC_MINOR__ >= 9)
+#  define __GCC4_has_attribute___copy__                0
+#  define __GCC4_has_attribute___designated_init__     0
+#  define __GCC4_has_attribute___externally_visible__  1
+#  define __GCC4_has_attribute___no_caller_saved_registers__ 0
+#  define __GCC4_has_attribute___noclone__             1
+#  define __GCC4_has_attribute___nonstring__           0
+#  define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
+#  define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9)
+#  define __GCC4_has_attribute___fallthrough__         0
+#  define __GCC4_has_attribute___fallthrough__         0
+#endif
+
+/* ${LINUX_SRC}/include/linux/compiler_attributes.h, around line 200
+ */
+#if __has_attribute(__fallthrough__)
+#  define fallthrough                    __attribute__((__fallthrough__))
+#else
+#  define fallthrough                    do {} while (0);  /* fallthrough */
+#endif
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#  include <stdio.h>
+#  include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#  undef  TEST_IGNORE
+#  define TEST_IGNORE() {}
+#endif
+
+#endif  /* __BR_COMMON_H */

c/phone-number/makefile

@@ -0,0 +1,51 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+# detect compiler.
+REALCC=$(realpath $(shell which $(CC)))
+CC_VERSION_TEXT=$(shell $(REALCC) --version 2>/dev/null | head -n 1)
+
+# fix discrepancies in compilers warnings. Only gcc and clang for now.
+ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
+CFLAGS += -Wimplicit-fallthrough
+else
+ifneq ($(findstring gcc,$(CC_VERSION_TEXT)),)
+CFLAGS := $(filter-out -Wimplicit-fallthrough%,$(CFLAGS))
+CFLAGS += -Wimplicit-fallthrough=5
+endif
+endif
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: ./*.c ./*.h
+	@echo Compiling $@
+	$(CC) $(ASANFLAGS) $(CFLAGS) test-framework/unity.c ./*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: ./*.c ./*.h
+	@echo Compiling $@
+	$(CC) $(CFLAGS) test-framework/unity.c ./*.c -o tests.out $(LIBS)

c/phone-number/phone_number.c

@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "phone_number.h"
+
+#define LEN_NUM   10
+#define LPAREN    '('
+
+/* this version is likely not very stable, due to poor scanf() capabilities
+ * I made it to offer an option to traditional strtok() or manual string
+ * parsing.
+ * Examples:
+ *    (1 (222-333.4444
+ *    1)))))) 222))) ...---...  333 ...---... 4444
+ * are both valid here, when they surely should not :-)
+ */
+static char *scan="%m[+(0-9]%*[()-. ]%m[0-9]%*[)-. ]%m[0-9]%*[-. ]%m[0-9]";
+
+char *phone_number_clean(const char *input)
+{
+    char *sn[4];
+    uint64_t num[4];
+    uint64_t *p = &*num;
+    int nmatch;
+    char *res;
+
+    if (!(res = malloc(LEN_NUM+1)))
+        return NULL;
+    memset(res, '0', LEN_NUM);
+    *(res+LEN_NUM) = 0;
+
+    nmatch = sscanf(input, scan, &sn[0], &sn[1], &sn[2], &sn[3]);
+
+    for (int i=0; i<nmatch; ++i) {
+        *(p+i) = atol(*sn[i] == LPAREN? sn[i]+1: sn[i]);
+        free(sn[i]);                              /* due to scanf %m */
+    }
+
+    switch (nmatch) {
+        case 2:
+            /* maybe 2 could be valid, like 333 3334444 ?
+             */
+        case 0:
+            return res;
+        case 1:                                   /* full number */
+            if (*p > 10000000000)                 /* 1 000 000 0000 */
+                *p -= 10000000000;
+            if (*p > 9999999999 ||                /* 999 999 9999 */
+                *p < 2000000000)                  /* 200 000 0000 */
+                return res;
+            break;
+        case 4:                                   /* country code */
+            if (*p != 1)
+                return res;
+            p++;                                  /* go to area number */
+            fallthrough;                          /* only gcc>=7 & clang>=12 */
+        case 3:                                   /* start with area number */
+            if (*p < 200 || *p > 999 ||
+                *(p+1) < 200 || *(p+1) > 999 ||
+                *(p+2) > 9999)
+                return res;
+            break;
+    }
+    /* we don't care if some num has random value here (initialized), snprintf
+     * will consume only what is needed to fill the number
+     */
+    snprintf(res, LEN_NUM+1, "%ld%ld%ld", *p, *(p+1), *(p+2));
+
+    return res;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg;
+    char *res;
+
+    for (arg=1; arg<ac; ++arg) {
+        res=phone_number_clean(av[arg]);
+        printf("orig = [%s]\n", av[arg]);
+        printf("\t-> [%s]\n", res);
+        free(res);
+    }
+}
+#endif

c/phone-number/phone_number.h

@@ -0,0 +1,10 @@
+#ifndef PHONE_NUMBER_H
+#define PHONE_NUMBER_H
+
+#define NUMBER_LENGTH 10
+
+char *phone_number_clean(const char *input);
+
+#endif
+
+#include "br-common.h"

c/phone-number/test_phone_number.c

@@ -0,0 +1,246 @@
+#include "test-framework/unity.h"
+#include "phone_number.h"
+#include <stdlib.h>
+
+static char *result = NULL;
+
+void setUp(void)
+{
+}
+
+void tearDown(void)
+{
+   free(result);
+   result = NULL;
+}
+
+static void test_cleans_the_number(void)
+{
+   const char input[] = "(223) 456-7890";
+   const char expected[] = "2234567890";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_cleans_numbers_with_dots(void)
+{
+   TEST_IGNORE();               // delete this line to run test
+   const char input[] = "223.456.7890";
+   const char expected[] = "2234567890";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_cleans_numbers_with_multiple_spaces(void)
+{
+   TEST_IGNORE();
+   const char input[] = "223 456   7890   ";
+   const char expected[] = "2234567890";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_when_9_digits(void)
+{
+   TEST_IGNORE();
+   const char input[] = "123456789";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_when_11_digits_does_not_start_with_a_1(void)
+{
+   TEST_IGNORE();
+   const char input[] = "22234567890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_valid_when_11_digits_and_starting_with_1(void)
+{
+   TEST_IGNORE();
+   const char input[] = "12234567890";
+   const char expected[] = "2234567890";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void
+test_valid_when_11_digits_and_starting_with_1_even_with_punctuation(void)
+{
+   TEST_IGNORE();
+   const char input[] = "+1 (223) 456-7890";
+   const char expected[] = "2234567890";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_when_more_than_11_digits(void)
+{
+   TEST_IGNORE();
+   const char input[] = "321234567890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_with_letters(void)
+{
+   TEST_IGNORE();
+   const char input[] = "123-abc-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_with_punctuations(void)
+{
+   TEST_IGNORE();
+   const char input[] = "123-@:!-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_if_area_code_starts_with_0(void)
+{
+   TEST_IGNORE();
+   const char input[] = "(023) 456-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_if_area_code_starts_with_1(void)
+{
+   TEST_IGNORE();
+   const char input[] = "(123) 456-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_if_exchange_code_starts_with_0(void)
+{
+   TEST_IGNORE();
+   const char input[] = "(223) 056-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void test_invalid_if_exchange_code_starts_with_1(void)
+{
+   TEST_IGNORE();
+   const char input[] = "(223) 156-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void
+test_invalid_if_area_code_starts_with_0_on_valid_11_digit_number(void)
+{
+   TEST_IGNORE();
+   const char input[] = "1 (023) 456-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void
+test_invalid_if_area_code_starts_with_1_on_valid_11_digit_number(void)
+{
+   TEST_IGNORE();
+   const char input[] = "1 (123) 456-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void
+test_invalid_if_exchange_code_starts_with_0_on_valid_11_digit_number(void)
+{
+   TEST_IGNORE();
+   const char input[] = "1 (223) 056-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+static void
+test_invalid_if_exchange_code_starts_with_1_on_valid_11_digit_number(void)
+{
+   TEST_IGNORE();
+   const char input[] = "1 (123) 156-7890";
+   const char expected[] = "0000000000";
+
+   result = phone_number_clean(input);
+
+   TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+
+int main(void)
+{
+   UnityBegin("test_phone_number.c");
+
+   RUN_TEST(test_cleans_the_number);
+   RUN_TEST(test_cleans_numbers_with_dots);
+   RUN_TEST(test_cleans_numbers_with_multiple_spaces);
+   RUN_TEST(test_invalid_when_9_digits);
+   RUN_TEST(test_invalid_when_11_digits_does_not_start_with_a_1);
+   RUN_TEST(test_valid_when_11_digits_and_starting_with_1);
+   RUN_TEST
+       (test_valid_when_11_digits_and_starting_with_1_even_with_punctuation);
+   RUN_TEST(test_invalid_when_more_than_11_digits);
+   RUN_TEST(test_invalid_with_letters);
+   RUN_TEST(test_invalid_with_punctuations);
+   RUN_TEST(test_invalid_if_area_code_starts_with_0);
+   RUN_TEST(test_invalid_if_area_code_starts_with_1);
+   RUN_TEST(test_invalid_if_exchange_code_starts_with_0);
+   RUN_TEST(test_invalid_if_exchange_code_starts_with_1);
+   RUN_TEST(test_invalid_if_area_code_starts_with_0_on_valid_11_digit_number);
+   RUN_TEST(test_invalid_if_area_code_starts_with_1_on_valid_11_digit_number);
+   RUN_TEST
+       (test_invalid_if_exchange_code_starts_with_0_on_valid_11_digit_number);
+   RUN_TEST
+       (test_invalid_if_exchange_code_starts_with_1_on_valid_11_digit_number);
+
+   return UnityEnd();
+}

c/pythagorean-triplet/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o tests.out  $(LIBS)

c/pythagorean-triplet/README.md

@@ -0,0 +1,62 @@
+# Pythagorean Triplet
+
+A Pythagorean triplet is a set of three natural numbers, {a, b, c}, for
+which,
+
+```text
+a**2 + b**2 = c**2
+```
+
+and such that,
+
+```text
+a < b < c
+```
+
+For example,
+
+```text
+3**2 + 4**2 = 9 + 16 = 25 = 5**2.
+```
+
+Given an input integer N, find all Pythagorean triplets for which `a + b + c = N`.
+
+For example, with N = 1000, there is exactly one Pythagorean triplet for which `a + b + c = 1000`: `{200, 375, 425}`.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Problem 9 at Project Euler [http://projecteuler.net/problem=9](http://projecteuler.net/problem=9)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/pythagorean-triplet/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/pythagorean-triplet/src/pythagorean_triplet.c

@@ -0,0 +1,89 @@
+#include <malloc.h>
+
+#include "pythagorean_triplet.h"
+
+#define POOL_SIZE 10
+
+/* V1: initial version
+ * V2: cormetic changes
+ * V3: add pool for realloc instead of single realloc
+ */
+void free_triplets(triplets_t *t)
+{
+    free(t->triplets);
+    free(t);
+}
+
+static triplets_t *new_triplet()
+{
+    triplets_t *t=malloc(sizeof(triplets_t));
+    if (t) {
+        t->count = 0;
+        t->pool  = 0;
+        t->triplets = NULL;
+    }
+    return t;
+}
+
+static triplets_t *add_triplet(triplets_t *t, const uint16_t a, const uint16_t b,
+                               const uint16_t c)
+{
+    /* we may directly call add_triplet() without new_triplet. Not used here,
+     * but could be useful if triplets_with_sum() would return NULL when no
+     * solution found.
+     */
+    if (! (t || (t = new_triplet())))
+        return NULL;
+
+    if (t->count == t->pool) {
+        t->pool += POOL_SIZE;
+        if (!(t->triplets = realloc(t->triplets, sizeof(triplets_t) +
+                                    t->pool * sizeof(triplet_t)))) {
+            free(t);
+            return NULL;
+        }
+    }
+    t->triplets[t->count] = (triplet_t) {a, b, c};
+    t->count++;
+    return t;
+}
+
+/* algorithm from : https://stackoverflow.com/a/2818750/3079831
+ */
+triplets_t *triplets_with_sum(uint16_t sum)
+{
+    int a, b, c;
+    triplets_t *t;
+
+    if (!(t = new_triplet()))
+        return NULL;
+    if (sum%2)
+        return t;
+
+    for (a = 1; a <= sum/3; a++) {
+        for (b = a + 1; b <= sum/2; b++) {
+            c = sum - a - b;
+            if (a*a + b*b == c*c)
+                if (!(t = add_triplet(t, a, b, c)))
+                    return NULL;
+        }
+    }
+    return t;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    resistor_band_t i[2];
+
+    for (; arg<ac-1; ++arg, ++arg) {
+        *i=atoi(av[arg]);
+        *(i+1)=atoi(av[arg+1]);
+        printf("color(%d, %d)=%d\n", i[0], i[1], color_code(i));
+    }
+}
+#endif

c/pythagorean-triplet/src/pythagorean_triplet.h

@@ -0,0 +1,34 @@
+#ifndef PYTHAGOREAN_TRIPLET
+#define PYTHAGOREAN_TRIPLET
+#include <stdlib.h>
+#include <stdint.h>
+
+typedef struct triplet {
+    uint16_t a;
+    uint16_t b;
+    uint16_t c;
+} triplet_t;
+
+typedef struct triplets {
+    size_t count;
+    size_t pool;
+    triplet_t *triplets;
+} triplets_t;
+
+triplets_t *triplets_with_sum(uint16_t sum);
+void free_triplets(triplets_t *triplet);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/raindrops/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/raindrops/README.md

@@ -0,0 +1,54 @@
+# Raindrops
+
+Your task is to convert a number into a string that contains raindrop sounds corresponding to certain potential factors. A factor is a number that evenly divides into another number, leaving no remainder. The simplest way to test if a one number is a factor of another is to use the [modulo operation](https://en.wikipedia.org/wiki/Modulo_operation).
+
+The rules of `raindrops` are that if a given number:
+
+- has 3 as a factor, add 'Pling' to the result.
+- has 5 as a factor, add 'Plang' to the result.
+- has 7 as a factor, add 'Plong' to the result.
+- _does not_ have any of 3, 5, or 7 as a factor, the result should be the digits of the number.
+
+## Examples
+
+- 28 has 7 as a factor, but not 3 or 5, so the result would be "Plong".
+- 30 has both 3 and 5 as factors, but not 7, so the result would be "PlingPlang".
+- 34 is not factored by 3, 5, or 7, so the result would be "34".
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+A variation on FizzBuzz, a famous technical interview question that is intended to weed out potential candidates. That question is itself derived from Fizz Buzz, a popular children's game for teaching division. [https://en.wikipedia.org/wiki/Fizz_buzz](https://en.wikipedia.org/wiki/Fizz_buzz)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/raindrops/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/raindrops/src/raindrops.c

@@ -0,0 +1,29 @@
+#include "raindrops.h"
+#include <stdio.h>
+
+char *convert(char result[], int drops)
+{
+    char *p=result;
+
+    if (!(drops%3)) p+=sprintf(p, "%s", "Pling");
+    if (!(drops%5)) p+=sprintf(p, "%s", "Plang");
+    if (!(drops%7)) p+=sprintf(p, "%s", "Plong");
+    if (p==result) sprintf(p, "%d", drops);
+    return result;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1, i;
+    char buffer[128];
+
+    for (; arg<ac; ++arg) {
+        i=atoi(av[arg]);
+        printf("raindrops(%d)=%s\n", i, convert(buffer, i));
+    }
+}
+#endif

c/raindrops/src/raindrops.h

@@ -0,0 +1,18 @@
+#ifndef RAINDROPS_H
+#define RAINDROPS_H
+
+char *convert(char result[], int drops);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/rational-numbers/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o tests.out  $(LIBS)

c/rational-numbers/README.md

@@ -0,0 +1,67 @@
+# Rational Numbers
+
+A rational number is defined as the quotient of two integers `a` and `b`, called the numerator and denominator, respectively, where `b != 0`.
+
+The absolute value `|r|` of the rational number `r = a/b` is equal to `|a|/|b|`.
+
+The sum of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ + r₂ = a₁/b₁ + a₂/b₂ = (a₁ * b₂ + a₂ * b₁) / (b₁ * b₂)`.
+
+The difference of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ - r₂ = a₁/b₁ - a₂/b₂ = (a₁ * b₂ - a₂ * b₁) / (b₁ * b₂)`.
+
+The product (multiplication) of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ * r₂ = (a₁ * a₂) / (b₁ * b₂)`.
+
+Dividing a rational number `r₁ = a₁/b₁` by another `r₂ = a₂/b₂` is `r₁ / r₂ = (a₁ * b₂) / (a₂ * b₁)` if `a₂` is not zero.
+
+Exponentiation of a rational number `r = a/b` to a non-negative integer power `n` is `r^n = (a^n)/(b^n)`.
+
+Exponentiation of a rational number `r = a/b` to a negative integer power `n` is `r^n = (b^m)/(a^m)`, where `m = |n|`.
+
+Exponentiation of a rational number `r = a/b` to a real (floating-point) number `x` is the quotient `(a^x)/(b^x)`, which is a real number.
+
+Exponentiation of a real number `x` to a rational number `r = a/b` is `x^(a/b) = root(x^a, b)`, where `root(p, q)` is the `q`th root of `p`.
+
+Implement the following operations:
+ - addition, subtraction, multiplication and division of two rational numbers,
+ - absolute value, exponentiation of a given rational number to an integer power, exponentiation of a given rational number to a real (floating-point) power, exponentiation of a real number to a rational number.
+
+Your implementation of rational numbers should always be reduced to lowest terms. For example, `4/4` should reduce to `1/1`, `30/60` should reduce to `1/2`, `12/8` should reduce to `3/2`, etc. To reduce a rational number `r = a/b`, divide `a` and `b` by the greatest common divisor (gcd) of `a` and `b`. So, for example, `gcd(12, 8) = 4`, so `r = 12/8` can be reduced to `(12/4)/(8/4) = 3/2`.
+
+Assume that the programming language you are using does not have an implementation of rational numbers.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Wikipedia [https://en.wikipedia.org/wiki/Rational_number](https://en.wikipedia.org/wiki/Rational_number)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/rational-numbers/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/rational-numbers/src/rational_numbers.c

@@ -0,0 +1,115 @@
+#include "rational_numbers.h"
+#include <stdlib.h>
+#include <math.h>
+
+#define N(r)  ((r).numerator)
+#define D(r)  ((r).denominator)
+
+/* Note. We should probably check for possible overflow in all
+ * functions below (not covered in exercise).
+ * To do this, a simple solution could be to make operations with
+ * long long (or some other method), and add a field in rational_t
+ * to express such overflow, division by zero, etc...
+ */
+
+/* Euclidean algorithm (by Donald Knuth) */
+rational_t reduce(rational_t r)
+{
+    int16_t a=abs(N(r)), b=abs(D(r)), t;
+
+    while (b != 0) {
+        t = b;
+        b = a % b;
+        a = t;
+    }
+    if (D(r) < 0)
+        a=-a;
+    return (rational_t) { N(r)/a, D(r)/a };
+}
+
+/* to avoid pow() for integers
+ * BUG: does not check for overflow
+ */
+static inline int power(int n, int p)
+{
+    int res=n;
+
+    if (p==0)
+        return 1;
+    while (--p)
+        res*=n;
+    return res;
+}
+
+/* All formulas below come from https://en.wikipedia.org/wiki/Rational_number
+ */
+rational_t add(rational_t r1, rational_t r2)
+{
+    return reduce((rational_t) {
+            N(r1) * D(r2) + N(r2) * D(r1),
+            D(r1) * D(r2)
+        });
+}
+
+rational_t subtract(rational_t r1, rational_t r2)
+{
+    return reduce((rational_t) {
+            N(r1) * D(r2) - N(r2) * D(r1),
+            D(r1) * D(r2)
+        });
+}
+
+rational_t multiply(rational_t r1, rational_t r2)
+{
+    return reduce((rational_t) {
+            N(r1) * N(r2),
+            D(r1) * D(r2)
+        });
+}
+
+rational_t divide(rational_t r1, rational_t r2)
+{
+    return reduce((rational_t) {
+            N(r1) * D(r2),
+            D(r1) * N(r2)
+        });
+}
+
+rational_t absolute(rational_t r)
+{
+    return (rational_t) {
+        abs(N(r)),
+        abs(D(r))
+    };
+}
+
+rational_t exp_rational(rational_t r, uint16_t n)
+{
+    return reduce((rational_t) {
+            power(N(r), n),
+            power(D(r), n)
+        });
+}
+
+float exp_real(uint16_t x, rational_t r)
+{
+    return powf((float)x, (float)N(r)/D(r));
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    rational_t r1, r2;
+
+    for (; arg<ac-1; ++arg, ++arg) {
+        r1.numerator=atoi(av[arg]);;
+        r1.denominator=atoi(av[arg+1]);;
+        r2=reduce(r1);
+        printf("reduce(%d, %d)=(%d, %d)\n", N(r1), D(r1), N(r2), D(r2));
+    }
+}
+#endif

c/rational-numbers/src/rational_numbers.h

@@ -0,0 +1,33 @@
+#ifndef RATIONAL_NUMBERS
+#define RATIONAL_NUMBERS
+
+#include <stdint.h>
+
+typedef struct {
+    int16_t numerator;
+    int16_t denominator;
+} rational_t;
+
+rational_t add(rational_t r1, rational_t r2);
+rational_t subtract(rational_t r1, rational_t r2);
+rational_t multiply(rational_t r1, rational_t r2);
+rational_t divide(rational_t r1, rational_t r2);
+rational_t absolute(rational_t r);
+rational_t exp_rational(rational_t r, uint16_t n);
+float exp_real(uint16_t x, rational_t r);
+rational_t reduce(rational_t r);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/resistor-color-duo/src/resistor_color_duo.c

@@ -4,10 +4,9 @@
 #include <stdlib.h>
 #endif
 
-resistor_band_t color_code(resistor_band_t *colors)
+resistor_band_t color_code(resistor_band_t colors[static 2])
 {
     resistor_band_t c1=*colors, c2=*(colors+1);
-
     return c1>=BLACK && c1<=WHITE && c2>=BLACK && c2<=WHITE? c1*10+c2: ERROR;
 }
 
@@ -20,7 +19,7 @@ int main(int ac, char **av)
     for (; arg<ac-1; ++arg, ++arg) {
         *i=atoi(av[arg]);
         *(i+1)=atoi(av[arg+1]);
-        printf("color(%d, %d)=%d\n", i[0], i[1], color_code(i));
+        printf("color(%d, %d)=%d\n", *i, *(i+1), color_code(i));
     }
 }
 #endif

c/resistor-color-duo/src/resistor_color_duo.h

@@ -15,7 +15,7 @@ typedef enum {
     ERROR=-1,
 } resistor_band_t;
 
-extern resistor_band_t color_code(resistor_band_t *);
+extern resistor_band_t color_code(resistor_band_t [static 2]);
 
 #ifdef TESTALL
 #undef  TEST_IGNORE

c/rna-transcription/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/rna-transcription/README.md

@@ -0,0 +1,57 @@
+# RNA Transcription
+
+Given a DNA strand, return its RNA complement (per RNA transcription).
+
+Both DNA and RNA strands are a sequence of nucleotides.
+
+The four nucleotides found in DNA are adenine (**A**), cytosine (**C**),
+guanine (**G**) and thymine (**T**).
+
+The four nucleotides found in RNA are adenine (**A**), cytosine (**C**),
+guanine (**G**) and uracil (**U**).
+
+Given a DNA strand, its transcribed RNA strand is formed by replacing
+each nucleotide with its complement:
+
+* `G` -> `C`
+* `C` -> `G`
+* `T` -> `A`
+* `A` -> `U`
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Hyperphysics [http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html](http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/rna-transcription/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/rna-transcription/src/rna_transcription.c

@@ -0,0 +1,37 @@
+#include <malloc.h>
+#include <string.h>
+#include "rna_transcription.h"
+
+static char C[256]={
+    ['G']='C', ['C']='G', ['T']='A', ['A']='U',
+};
+
+char *to_rna(const char *dna)
+{
+    char *rna=malloc(strlen(dna+1)), *p;
+
+    if (rna) {
+        for (p=rna; *dna; p++, dna++) {
+            if (!(*p=C[(int)*dna])) {
+                free(rna);
+                return NULL;
+            }
+        }
+        *p=0;
+    }
+    return rna;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+
+    for (; arg<ac; ++arg) {
+        printf("rna(%s)=%s\n", av[arg], to_rna(av[arg]));
+    }
+}
+#endif

c/rna-transcription/src/rna_transcription.h

@@ -0,0 +1,18 @@
+#ifndef RNA_TRANSCRIPTION_H
+#define RNA_TRANSCRIPTION_H
+
+char *to_rna(const char *dna);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/roman-numerals/GNUmakefile

@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out

c/roman-numerals/README.md

@@ -0,0 +1,81 @@
+# Roman Numerals
+
+Write a function to convert from normal numbers to Roman Numerals.
+
+The Romans were a clever bunch. They conquered most of Europe and ruled
+it for hundreds of years. They invented concrete and straight roads and
+even bikinis. One thing they never discovered though was the number
+zero. This made writing and dating extensive histories of their exploits
+slightly more challenging, but the system of numbers they came up with
+is still in use today. For example the BBC uses Roman numerals to date
+their programmes.
+
+The Romans wrote numbers using letters - I, V, X, L, C, D, M. (notice
+these letters have lots of straight lines and are hence easy to hack
+into stone tablets).
+
+```text
+ 1  => I
+10  => X
+ 7  => VII
+```
+
+There is no need to be able to convert numbers larger than about 3000.
+(The Romans themselves didn't tend to go any higher)
+
+Wikipedia says: Modern Roman numerals ... are written by expressing each
+digit separately starting with the left most digit and skipping any
+digit with a value of zero.
+
+To see this in practice, consider the example of 1990.
+
+In Roman numerals 1990 is MCMXC:
+
+1000=M
+900=CM
+90=XC
+
+2008 is written as MMVIII:
+
+2000=MM
+8=VIII
+
+See also: http://www.novaroma.org/via_romana/numbers.html
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+The Roman Numeral Kata [http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals](http://codingdojo.org/cgi-bin/index.pl?KataRomanNumerals)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd

c/roman-numerals/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)

c/roman-numerals/src/roman_numerals.c

@@ -0,0 +1,73 @@
+#include "roman_numerals.h"
+#include <stdio.h>
+#include <string.h>
+#include <malloc.h>
+
+static struct conv_s {
+    unsigned char r;
+    unsigned d;
+} conv[] = {
+    { 'M', 1000 },
+    { 'D',  500 },
+    { 'C',  100 },
+    { 'L',   50 },
+    { 'X',   10 },
+    { 'V',    5 },
+    { 'I',    1 }
+};
+
+/* rules could differ (like IIII/VIIII instead of IV/IX), so it is better not
+ * to harcode values like 4, 9, 40, 90 etc...
+ * Example: the Colosseum gate 44 was written XLIIII, and not XLIV.
+ * we can therefore add a parameter in function below, and add a rule in
+ * the code to easily return a different notation.
+ */
+char *to_roman_numeral(unsigned int n /*, int notation */ )
+{
+    unsigned cur=0, mult, pos=0, i;
+    char res[64]={0}, *to;
+
+    /* max number = 3999 = MMMCMXCIX */
+    if (n >= 4000)                                /* could be different if we */
+        return NULL;                              /* accept the 5000 sign */
+
+    while (n) {
+        /* we could : switch (notation) {
+         *              case ROMAN_RULE:
+         */
+        if ((mult=n/conv[cur].d)) {               /* >= current multiplier */
+            if (mult%5==4) {                      /* 4 & 9 */
+                res[pos++]=conv[cur].r;
+                res[pos++]=conv[cur-mult/4].r;    /* 4/4=1, 9/4=2 */
+            } else {                              /* 1-3 & 5-8 */
+                if (mult >= 5)
+                    res[pos++]=conv[cur-1].r;
+                for (i=mult%5; i>0; --i)
+                    res[pos++]=conv[cur].r;
+            }
+            n-=mult*conv[cur].d;
+        }
+        cur+=2;
+    }
+    if ((to=malloc(pos+1)))
+        memcpy(to, res, pos+1);
+    return to;
+}
+
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+#include <stdlib.h>
+int main(int ac, char **av)
+{
+    int arg=1;
+    unsigned i;
+
+    for (; arg<ac; ++arg) {
+        i=atoi(av[arg]);
+        printf("roman(%d)=%s\n", i, to_roman_numeral(i));
+    }
+}
+#endif

c/roman-numerals/src/roman_numerals.h

@@ -0,0 +1,20 @@
+#ifndef ROMAN_NUMERALS_H
+#define ROMAN_NUMERALS_H
+
+#define ROMAN_RULE 0
+
+char *to_roman_numeral(unsigned int number);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif

c/run-length-encoding/GNUmakefile

@@ -0,0 +1,56 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+# 1) copy it into exercise directory
+# 2) add ex.h to exercise include file
+# 3) add ex.c to exercise source code, and create a suitable main function
+# 4) use make with one of the following targets :
+#   all: compile and run all predefined tests.
+#   nowarn: compile with no -Werror, and run all predefined tests
+#   debug: compile with -DDEBUG and run all predefined tests
+#   mem: perform memcheck with all tests enabled
+#   unit: build standalone (unit) bimary
+#   unitnowarn: build standalone (unit) binary with -Werror disabled
+#   unitdebug: build standalone binary with -DDEBUG
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all nowarn debug mem unit unitnowarn unitdebug standalone
+
+default: all
+
+ALLSOURCES:=$(wildcard ./*.c)
+TESTSOURCES:=$(wildcard ./test_*.c)
+SRC:=$(filter-out $(TESTSOURCES),$(ALLSOURCES))
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+nowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+nowarn: clean all
+
+debug: CFLAGS+=-DDEBUG
+debug: all
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unitnowarn: CFLAGS:=$(filter-out -Werror,$(CFLAGS))
+unitnowarn: clean unit
+
+unitdebug: CFLAGS+=-DDEBUG
+unitdebug: clean unit
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: *.c *.h
+	$(CC) $(CFLAGS) $(SRC) -o tests.out  $(LIBS)

c/run-length-encoding/HELP.md

@@ -0,0 +1,63 @@
+# Help
+
+## Running the tests
+
+Get the first test compiling, linking and passing by following the [three rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test` task.
+
+```console
+$ make test
+```
+
+Create just the functions you need to satisfy any compiler errors and get the test to fail.
+Then write just enough code to get the test to pass.
+Once you've done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your implementation for readability and expressiveness and then go on to the next test.
+
+Try to use standard C99 facilities in preference to writing your own low-level algorithms or facilities by hand.
+
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit run_length_encoding.c run_length_encoding.h` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [C track's documentation](https://exercism.org/docs/tracks/c)
+- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+Make sure you have read the "Guides" section of the [C track][c-track] on the Exercism site.
+This covers the basic information on setting up the development environment expected by the exercises.
+
+## Submitting Incomplete Solutions
+
+If you are struggling with a particular exercise, it is possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+## Resources
+
+To get help if having trouble, you can use the following resources:
+
+- [StackOverflow][] can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.
+- [CPPReference][] can be used to look up information on C concepts, operators, types, standard library functions and more.
+- [TutorialsPoint][] has similar content as CPPReference in its C programming section.
+- [The C Programming][K&R] book by K&R is the original source of the language and is still useful today.
+
+[c-track]: https://exercism.io/my/tracks/c
+[stackoverflow]: http://stackoverflow.com/questions/tagged/c
+[cppreference]: https://en.cppreference.com/w/c
+[tutorialspoint]: https://www.tutorialspoint.com/cprogramming/
+[K&R]: https://www.amazon.com/Programming-Language-2nd-Brian-Kernighan/dp/0131103628/