using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var x = new Class1();

        x.NewMethod("Ahmad Alweshahi");

    }

}

​

​

​

​

public class  Class1{

​

        public string Display()

        {

            return ("I m in Display");

        }

​

        public string Print()

        {

            return ("I m in Print");

        }

}

​

 public static class XX

    {

         public static void NewMethod(this Class1 ob,string yyy)

        {

            Console.WriteLine("Hello I m extended method, " + yyy);

        }

    }