fib.c

#include <stdio.h>

main
{
  printf ("%d\n", fib(10));
}

int fib (int num)
{
  if (num < 2)
    return num;
  else return fib(num - 1) + fib(num - 2);
}

$ cc fib.c
fib.c:4:1: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘{’ token