5
120
#include<stdio.h>
int sum(int n)
{
if(n==1) return 1;
return sum(n-1)*n;
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF){
printf("%d\n",sum(n));
}
return 0;
}
原文:http://blog.csdn.net/qq_16767427/article/details/38109805