using System;

​

public abstract class Animal                //Animal is an abstract class because it has the keyword abstract in its defintion

{

    public abstract void Walk();            //Walk is an abstract method because it has the abstract keyword and no definition

    public abstract void Run(int legs);     //Run is an abstract method because it has the abstract keyword and no definition

    public void Eat()                       //Eat is a concerte method as it has method definition and not marked as abstract

    {

        Console.WriteLine("Animal is Eating");

    }

}

​

public class Tiger: Animal                  //Tiger class inherits the abstract Animal class

{

    public override void Walk()             //Tiger class implements the abstract Walk class

    {

        Console.WriteLine("Tiger walks on four legs");

    }

}

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}