using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

                var d = new D();

        d.MMMM();

        var i = d as I;

        d.MMMM();

        d.MMMM2();

        // THIS WILL NOT COMPILE

        // d.MMMM3();

        var dddd = d as II;

        // THIS WILL COMPILE

        dddd.MMMM3();

        Console.WriteLine("Hello World2");

    }

}

​

    public abstract class C {

    public void MMMM() {

    }

}

​

public interface I{

    void MMMM();

}

​

public interface II{

    void MMMM2();

    void MMMM3();

}

​

public class D : C, I,II

{

    public void MMMM2(){}

    void  II.MMMM3(){}

}

​