/**
 * file: main.c
 * author: 简单教程(www.twle.cn)
 *
 * Copyright © 2015-2065 www.twle.cn. All rights reserved.
 */

#include <stdio.h>

int main()
{
    int i;
    int fact(int);
    for(i=0;i<6;i++){
        printf("%d!=%d\n",i,fact(i));
    }
}
int fact(int j)
{
    int sum;
    if(j==0){
        sum=1;
    } else {
        sum=j*fact(j-1);
    }
    return sum;
}

0!=1
1!=1
2!=2
3!=6
4!=24
5!=120