//Main:
复制代码 代码如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Factorial
{
class Program
{
static void Main(string[] args)
{
Function obj = new Function();
Console.WriteLine("Would you like to know which number of Factorial：");
int number = Convert.ToInt32(Console.ReadLine());
Console.WriteLine();
Console.Write("The Fibonacci of {0} is：{1}", number, obj.Factorial(number));
Console.WriteLine();
Console.Write("The FactorialRecursion of {0} is：{1}", number, obj.FactorialRecursion(number));
Console.ReadKey();
}
}
}

//Class:
复制代码 代码如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Factorial
{
class Function
{
/// <summary>
/// Factorial定义为：
/// ┌ 1 n=0
/// N!=│
/// └ n(n-1)! n>0
/// </summary>
/// <param name="number"></param>
/// <returns></returns>
public int Factorial(int number)
{
if (number != 0)
{
return number * Factorial(number - 1);
}
else if (number == 0)
{
return 1;
}
return number;
}

public int FactorialRecursion(int number)
{
int F = 1;
for (int i = 1; i <= number; i++)
{
F *= i;
}
return F;
}
}
}

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