C: sum of multiples + complex numbers

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