每日一编C-8

来源：http://blog.youkuaiyun.com/yueyawanbian/article/details/23861229

#include <stdio.h>
//递归实现阶乘 
long long int factorial(int n,long long int r)
{
	long long int x=r;
	if(n>1)
	{
		x*=factorial(n-1,n);
	}else
	{
		x*=n;
	}
	return x;
}
int main()
{
	long long int r=1;//result
	int n;//number
	printf("Input n:\n");
	scanf("%d",&n);
	r=factorial(n,r);
	printf("%d!=%lld",n,r);
	return 0;
}