using System;

public class Program

{

    public static void Main()

    {

        var redBeard = new Dog();

​

        // outputs "yum yum"

        redBeard.Eat();

        // outputs "woof woof"

        redBeard.MakeSound();

​

​

        var kayden = new Cat();

​

        // outputs "yum yum"

        kayden.Eat();

        // outputs "meow meow"

        kayden.MakeSound();

    }

}

​

public abstract class Animal {

    public void Eat () {

        Console.WriteLine("yum yum");

    }

​

   public abstract void MakeSound();

}

​

public class Dog : Animal {

  public override void MakeSound() {

        Console.WriteLine("woof woof");

    }

}

​

public class Cat : Animal {

   public override void MakeSound() {

        Console.WriteLine("meow meow");

    }

}