用C#写的一个阶乘

using System;

namespace ConsoleApplication1
{
    /// <summary>
    /// Class1 的摘要说明。
    /// </summary>
    class Class1
    {  
        ///   <summary>  
        ///   应用程序的主入口点。  
        ///   </summary>  
          
    
        int n;  
        public int function(int i)  
        {  
            if( i <= 1 )
            {
                return 1;
            }
            else    
            {      
                int s=i*function(i-1);  
                return s;  
            }  
        }  
    
            
        static void Main(string[] args)  
        {  
            //  
            //   TODO:   在此处添加代码以启动应用程序  
            //            
            Console.WriteLine("输入数字N:");            
    
            Class1 c1=new Class1();
            try
            {
                c1.n = Convert.ToInt32(Console.ReadLine());  
            }
            catch(FormatException e)
            {
                Console.WriteLine(e.Message);
            }
    
            int nResult=c1.function(c1.n);  
            Console.WriteLine(nResult);  
        }  
    }  
}