p4.cpp

好东西,绝对是好东西,我向大家推荐

#include <iostream.h>
int main()
{
	long long N;
	long long n;
	int i;
	while (cin>>N)
	{
		i=N;n=1;
		if(N==0) cout<<"1"<<endl;
		else
		{
			while(i!=1)
			{
				n=n*i;
				i--;
			}
		}
		cout<<n<<endl;
	}
}