initial commit

c/armstrong-numbers/GNUmakefile

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+# the original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means we need to edit 'makefile' for different builds (DEBUG, etc...),
+# which is not practical at all.
+#
+# I hope this will be use-able for next exercises...
+
+#include gmsl
+include makefile
+
+manual=-DUNIT_TEST
+debug=$(manual) -DDEBUG
+
+.PHONY: manual debug
+
+manual debug: src/*.c src/*.h
+	$(CC) $($@) src/*.c -o $@.out
+#debug: src/*.c src/*.h
+#	$(CC) $(DEBUG) src/*.c -o $@.out

c/armstrong-numbers/README.md

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+# Armstrong Numbers
+
+An [Armstrong number](https://en.wikipedia.org/wiki/Narcissistic_number) is a number that is the sum of its own digits each raised to the power of the number of digits.
+
+For example:
+
+- 9 is an Armstrong number, because `9 = 9^1 = 9`
+- 10 is *not* an Armstrong number, because `10 != 1^2 + 0^2 = 1`
+- 153 is an Armstrong number, because: `153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153`
+- 154 is *not* an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
+
+Write some code to determine whether a number is an Armstrong number.
+
+## 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/Narcissistic_number](https://en.wikipedia.org/wiki/Narcissistic_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/armstrong-numbers/makefile

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+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+###
+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/armstrong-numbers/src/armstrong_numbers.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include "armstrong_numbers.h"
+
+static inline int power(int n, int p) {
+    int res=n;
+
+    /* useless here
+     * if (p==0)
+     *   return 1;
+     */
+    while (--p)
+        res*=n;
+    return res;
+}
+
+bool is_armstrong_number(int candidate)
+{
+    int p=1, r=0, tmp=candidate;
+
+    while (tmp/=10)
+        p++;
+
+    for (tmp=candidate; tmp; tmp /=10)
+        r+=power(tmp%10, p);
+    return r==candidate;
+}
+
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1, n;
+
+    for (; arg<ac; ++arg) {
+        n=atoi(av[arg]);
+        printf("armstrong(%d)=%d\n", n, is_armstrong_number(n));
+    }
+
+}
+#endif

c/armstrong-numbers/src/armstrong_numbers.h

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+#ifndef ARMSTRONG_NUMBERS
+#define ARMSTRONG_NUMBERS
+
+#include <stdbool.h>
+
+bool is_armstrong_number(int candidate);
+
+#endif