modernc.org/99c@v1.0.1-0.20181109153923-a9e8197063d9/examples/prof/fib.c (about) 1 #include <stdlib.h> 2 #include <stdio.h> 3 4 int fib(int n) 5 { 6 switch (n) { 7 case 0: 8 return 0; 9 case 1: 10 return 1; 11 default: 12 return fib(n - 1) + fib(n - 2); 13 } 14 } 15 16 int main(int argc, char **argv) 17 { 18 if (argc != 2) { 19 return 2; 20 } 21 22 int n = atoi(argv[1]); 23 if (n <= 0 || n > 40) { 24 return 1; 25 } 26 27 printf("%i\n", fib(n)); 28 }