using System;

public class Program

{

    public static void Main()

    {

        ReverseString();

    }

    static void ReverseString()

    {

        const string name = "Hello World";

        var mystring = name.ToCharArray();

​

        Array.Reverse(mystring);

        Array.Reverse(mystring);

        Console.WriteLine(new string(mystring));

    }

}