A-M baby

Task/Mutual-recursion/C/mutual-recursion.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/* let us declare our functions; indeed here we need
+   really only M declaration, so that F can "see" it
+   and the compiler won't complain with a warning */
+int F(const int n);
+int M(const int n);
+
+int F(const int n)
+{
+  return (n == 0) ? 1 : n - M(F(n - 1));
+}
+
+int M(const int n)
+{
+  return (n == 0) ? 0 : n - F(M(n - 1));
+}
+
+int main(void)
+{
+  int i;
+  for (i = 0; i < 20; i++)
+    printf("%2d ", F(i));
+  printf("\n");
+  for (i = 0; i < 20; i++)
+    printf("%2d ", M(i));
+  printf("\n");
+  return EXIT_SUCCESS;
+}