using System;

​

namespace MyApplication

{

    // 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 Cat : Animal

    {

        public override void animalSound()

        {

            // The body of animalSound() is provided here

            Console.WriteLine("The cat says: meows");

        }

    }

​

    class Program

    {

        static void Main(string[] args)

        {

            Cat myCat = new Cat();  // Create a Cat object

            myCat.animalSound();

            myCat.sleep();

        }

    }

}