用各种语言写出n!的算法

 1  class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5             Console.WriteLine("请输入一个数！");
 6             int input =Convert.ToInt32(Console.ReadLine());
 7            int result= GetFactorialValue(input);
 8            Console.WriteLine("{0}的阶乘的值是：{1}", input, result);
 9            Console.ReadKey();
10         }
11         /// <summary>
12         /// 获得阶乘的值
13         /// </summary>
14         /// <param name="input"></param>
15         /// <returns></returns>
16         private static int GetFactorialValue(int input)
17         {

18                 if (input == 0 || input == 1)
19                 {
20                     return 1;
21                 }
22                 return input*GetFactorialValue(input - 1);
23         }
24     }