C: sum of multiples + complex numbers

c/sum-of-multiples/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.
+# - 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/sum-of-multiples/README.md

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+# Sum Of Multiples
+
+Given a number, find the sum of all the unique multiples of particular numbers up to
+but not including that number.
+
+If we list all the natural numbers below 20 that are multiples of 3 or 5,
+we get 3, 5, 6, 9, 10, 12, 15, and 18.
+
+The sum of these multiples is 78.
+
+## 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 Problem 1 at Project Euler [http://projecteuler.net/problem=1](http://projecteuler.net/problem=1)
+
+## 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/sum-of-multiples/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.
+
+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/sum-of-multiples/src/sum_of_multiples.c

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+#include <stdio.h>
+#include <malloc.h>
+
+/* V1: initial version
+ * V2: bug fix: force full unsigned allocation instead of bytes.
+ */
+#include "sum_of_multiples.h"
+
+#define BITS (sizeof(unsigned)*8)
+
+#define getbit(i) (!!(sieve[(i) / BITS] & (1 << ((i) % BITS))))
+#define setbit(i) (sieve[(i) / BITS] |= (1 << ((i) % BITS)))
+
+/* use a kind of eratosthenes's sieve, to avoid the trivial solution :-)
+ */
+unsigned sum(const unsigned *f, const size_t n, const unsigned l)
+{
+    unsigned sieve_size = (l-1)/BITS+1;
+    unsigned num, i, res=0;
+    unsigned *sieve;
+
+    sieve = calloc(sieve_size, sizeof(unsigned)); /* l bits array */
+    if (!sieve)
+        return 0;
+    for (i=0; i<n; ++i) {
+        if (f[i]) {
+            for (num=f[i]; num<l; num+=f[i]) {
+                if (!getbit(num)) {
+                    res+=num;
+                    setbit(num);
+                }
+            }
+
+        }
+    }
+    free(sieve);
+    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)
+{
+    unsigned input[256];
+    int last, i;
+    if (ac>2) {
+        last=atol(av[1]);
+        for (i=2; i<ac; ++i) {
+            input[i-2]=atoi(av[i]);
+        }
+        printf("sum(..., %u, %u)=%u\n", i-2, last,
+               sum(input, (unsigned)i-2, (unsigned)last));
+    }
+}
+#endif

c/sum-of-multiples/src/sum_of_multiples.h

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+#ifndef SUM_OF_MULTIPLES_H
+#define SUM_OF_MULTIPLES_H
+
+#include <stddef.h>
+
+unsigned int sum(const unsigned int *factors,
+                 const size_t number_of_factors, const unsigned int limit);
+
+/* 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