计算10! 的值.

计算10! 的值.

using System;
using System.Collections.Generic;
using System.Text;

namespace ExFactorial
{
class Factorial
{
public double factorial(int num)
{
switch (num)
{
case 1:
return 1;
default :
return num * factorial(num - 1);
}

}
static void Main(string[] args)
{
Console.WriteLine("输入一个整数：");
int num=Convert.ToInt32 (Console.ReadLine());
Factorial f = new Factorial();
Console.WriteLine("{0}!的值为{1}", num, f.factorial(num));
}
}
}

 

 

public static int fac(int num){
		if(num==1)
			return 1;
		else
			return num * fac(num-1);
	}
	
	public static int nofac(int num){
		int n =1;
		if(num==1)
			return 1;
		else
			for(int i=num;i>0;i--){
				n = n*num;
				num--;
			}
		return n;
	}