using System;

// Abstract class

abstract class Animal

{

  // Abstract method (does not have a body)

  public abstract void animalSound();

  // Regular method

  public void sleep()

  {

    Console.WriteLine("Zzz");

  }

}

​

// Derived class (inherit from Animal)

class Pig : Animal

{

  public override void animalSound()

  {

    // The body of animalSound() is provided here

    Console.WriteLine("The pig says: wee wee");

  }

}

​

public class Program

{

  public static void Main(string[] args)

  {

    Pig myPig = new Pig(); // Create a Pig object

    myPig.animalSound();  // Call the abstract method

    myPig.sleep();  // Call the regular method

  }

}