public class Hello1

{

   public static void Main()

   {

      System.Console.WriteLine("Hello, World!");

   }

}

using System;

public class Hello2

{

   public static void Main()

   {

      Console.WriteLine("Hello, World!");

   }

}

// Hello3.cs

// 参数：A B C D

using System;

public class Hello3

{

   public static void Main(string[] args)

   {

      Console.WriteLine("Hello, World!");

      Console.WriteLine("You entered the following {0} command line arguments:",

         args.Length );

      for (int i=; i < args.Length; i++)

      {

         Console.WriteLine("{0}", args[i]);

      }

   }

}

using System;

public class Hello4

{

   public static int Main(string[] args)

   {

      Console.WriteLine("Hello, World!");

      return ;

   }

}