using System;

public abstract class G

{

  public abstract void method1();

}

​

public class child1 :G

{

  public override void method1()

  {

  Console.WriteLine("Child 1");

  }

}

​

public class child2:G

{

 public override void method1()

{

  Console.WriteLine("Child 2");

}

}

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Abstract class");

        G obj;

        obj=new child1();

        obj.method1();

        obj=new child2();

        obj.method1();

    }

}