#include <stdio.h> typedef void (*END_OF_END)(unsigned long); void fibonacci(int, unsigned long, unsigned long, void(*)(unsigned long)); void notify(unsigned long res) {   printf("Ultimate result: %lu\n" res);   exit(0); } /* Note: Fibonacci number might overflow! */ void fibonacci(int n, unsigned long v1, unsigned long v2, void(*notify)(unsigned long)) {   if (n <= 0) notify(v2);   fibonacci(n - 1, v2, v1 + v2, notify); } int main(void) {   fibonacci(100 - 2, 1, 1, notify);   return 0; }