factorial 두가지 방법 [C 언어]

#include 

int factorial(int n)
{
  int res, i;
  
  res = 1;
  for(i = 2; i <= n; i++) {
    res *= i;
  }
  return res;
}

int factorial2(int n)
{
  if (n == 1)
    return 1;
    
  return n * factorial2(n - 1);
}

int main(void) {
  printf("Hello World\n");
  printf("%d\n", factorial(5));
  printf("%d\n", factorial2(5));
  return 0;
}