C: secret handshake

c/secret-handshake/src/secret_handshake.c

@@ -0,0 +1,38 @@
+#include <malloc.h>
+#include "secret_handshake.h"
+
+static const char *C[] = { "wink", "double blink", "close your eyes", "jump" };
+
+const char **commands(size_t n)
+{
+    int i=0, c=0, s=1, e=4;
+    const char **r=calloc(4, sizeof(char *));
+
+    if (n & 020) i=3, s=-1, e=-1;                 /* reverse loop params */
+
+    for (; i!=e; i+=s)
+        if (n & (1<<i))
+            r[c++]=*(C+i);
+    return 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;
+    int i;
+    const char **res;
+    for (; arg<ac-1; ++arg, ++arg) {
+        i=atoi(av[arg]);
+        res=commands(i);
+        printf("handshake(%d)=\n", i);
+        for (i=0; res[i]; ++i)
+            printf("[%s] ", res[i]);
+        putchar('\n');
+        free(res);
+    }
+}
+#endif

c/secret-handshake/src/secret_handshake.h

@@ -0,0 +1,20 @@
+#ifndef SECRET_HANDSHAKE_H
+#define SECRET_HANDSHAKE_H
+
+#include <stddef.h>
+
+const char **commands(size_t 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