using System;

using System.Collections;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        #region Contravarient Usage Types

        //Type 1 - Passing objects

            Toyota MyCar = new Toyota();

            Honda MyWifeCar  = new Honda();

            Console.WriteLine("============================");

            ShowColor(MyCar); //Contravarient 

            ShowColor(MyWifeCar); //Contravarient 

        //Type 2 -  Passing List<Objects>

            List<Car> mycars = new List<Car>();

            mycars.Add(MyCar);

            mycars.Add(MyWifeCar);

            Console.WriteLine("============================");

            ShowColor(mycars);

        //Type 3 - Passing IEnumerable<Objects>

            IEnumerable<Car> myIEnumCars = mycars;

            Console.WriteLine("============================");

            ShowColor(myIEnumCars);

        //Type4 - Passing Delegates

            ContraVarientDelegateType<Car> mydel = ShowColor; // Using Named Method

            ContraVarientDelegateType<Car> mydel1 = (car) =>  car.DisplayColor(); // Using Unanymous Or Lamda Expression

        Console.WriteLine("============================");

            mydel(MyCar);

            mydel1(MyWifeCar);

        #endregion 

    }

    #region Contravarient Methods

    delegate void ContraVarientDelegateType <in T> (T a);

    private static void ShowColor(Car car)

    {

        car.DisplayColor();

    }

    private static void ShowColor(List<Car> cars)

    {

        Console.WriteLine("List of Car colors ==>: ");

        foreach(Car displaycar in cars)

            displaycar.DisplayColor();

    }

        private static void ShowColor(IEnumerable<Car> cars)

    {

        Console.WriteLine("List of IEnum Car colors ==>: ");

        foreach(Car displaycar in cars)

            displaycar.DisplayColor();

    }

    #endregion 

}

​

​

public class Car

{

    private string color = "red";

    public virtual void DisplayColor()

    {

        Console.WriteLine(" color : " + color );

    }

}

​

public class Toyota : Car

{ 

    private string color = "Totota red";

    public override void DisplayColor()

    {

        Console.WriteLine(" color : " + color );

    }

}

​

public class Honda : Car

{

    private string color = "Honda red";

    public override void DisplayColor()

    {

        Console.WriteLine("color : " + color );

    }

}