易百教程

using System;

namespace MyApplication {

   class Factorial {

      public int display(int n) {
         int res = 1;
         while (n != 1) {
            res = res * n;
            n = n - 1;
         }
         return res;
      }

      static void Main(string[] args) {

         int value = 5;
         int ret;

         Factorial fact = new Factorial();
         ret = fact.display(value);
         Console.WriteLine("Value is : {0}", ret );
         Console.ReadLine();
      }
   }
}