1~n的阶乘递归算法

#include <stdio.h>
int fun(int n)
{
  if(n>1)
     return n*fun(n-1);
  else
     return 1;
}

int main()
{
  int num;
  printf("Please input a number:");
  scanf("%d",&num);
  printf("%d\n",fun(num));
}