//1. An abstract class is a restricted class that cannot instantiate directly. You need to inherit it from another class. 

//   This behaves like a base class and is designed to be inherited from subclasses that can implement or override its methods.

//2. An abstract base class can provide implementation of members, but the abstract members have no implementation in their home abstract class, 

//   so they have to be implemented in the derived(child) class. When using an abstract method, 

//   its declaration does not provide any actual implemention; it is provided by a method override.

​

​

using System;

​

//Here is the base class.

public class Animal

{

    // Fields and properties of base class.

    public string name;

    private double weight;

    public void EatFood()

    {

        Console.WriteLine("Animal eating... "+ name);

    }

    public void Breed()

    {

        Console.WriteLine("Breeding... " + name);

    }

}

​

//This is the Chicken class

public class Chicken : Animal 

{

    public Chicken(string n)

    {

        this.name = n;  

    }

    public void Cluck()

    {

        Console.WriteLine("Clucking...");

    }

    public void LayEgg()

    {

        Console.WriteLine("Laying egg...");

    }

    public void EatFood() 

    {

        Console.WriteLine("Chicken eating... "+ name);

    }

    public void Breed()

    {

        Console.WriteLine("Chicken breed is... " + name);

    }

}

​

//This is creating the Cow class.

public class Cow : Animal

{

    public Cow(string n)

    {

        this.name = n;

    }

    public void Moo()

    {

        Console.WriteLine("Mooing...");

    }

    public void SupplyMilk()

    {

        Console.WriteLine("Supplying milk...");

    }

    public new void EatFood()

    {

        Console.WriteLine("Cow is eating... "+ name);

    }

    public new void Breed()

    {

        Console.WriteLine("Cow breed... " + name);

    }

}

​

//Below i am testing a normal animal, a new chicken and a new cow\.

public class Program

{

        public static void Main()

    {

        Animal A1 = new Animal();

        A1.name = "Animal";

        A1.Breed();

        A1.EatFood();

        Animal A2 = new Chicken("Robert");  

        A2.Breed();

        A2.EatFood();

        ((Chicken)A2).Cluck(); 

        Animal A4 = new Cow("Cowy"); 

        A4.Breed();

        A4.EatFood();

        ((Cow)A4).Moo();

    }

}

​

​

​

​