using System;

using System.Collections.Generic;

​

// Define the base class, Car. The class defines two methods, DescribeCar and ShowDetails.

// DescribeCar calls ShowDetails, and each derived class also defines a ShowDetails method.

// The example tests which version of ShowDetails is selected, the base class method or the derived class method.

public class Car

{

    public string GetTypeName()

    {

        return String.Format("{0,12}", GetType().Name + ":");

    }

    public void DescribeCar()

    {

        Console.Write("{0} (Base) Four wheels and an engine. ", GetTypeName());

        ShowDetails(false);

    }

    public virtual void ShowDetails(bool showClassName = true)

    {

        if (showClassName)

        {

            Console.Write("{0} ", GetTypeName());

        }

        Console.WriteLine("(Base) Standard transportation.");

    }

}

​

// Define the derived classes.

​

// The ConvertibleCar class uses the new modifier to acknowledge that ShowDetails hides the base class method.

public class Convertible : Car

{

    public new void ShowDetails(bool showClassName = true)

    {

        if (showClassName)

        {

            Console.Write("{0} ", GetTypeName());

        }

        Console.WriteLine("(New)  A roof that opens up.");

    }

}

​

// The Minivan class uses the override modifier to specify that ShowDetails extends the base class method.

public class Minivan : Car

{

    public override void ShowDetails(bool showClassName = true)

    {

        if (showClassName)

        {

            Console.Write("{0} ", GetTypeName());

        }

        Console.WriteLine("(Over) Carries seven people.");

    }

}

public class Program

{

    public const string line = "----------";

    public static void Main()

    {

        // Declare objects of the derived classes and test which version of ShowDetails is run, base or derived.

        TestCars1();

        // Declare objects of the base class, instantiated with the derived classes, and repeat the tests.

        TestCars2();

        // Declare objects of the derived classes and call ShowDetails directly.

        TestCars3();

        // Declare objects of the base class, instantiated with the derived classes, and repeat the tests.

        TestCars4();

    }

    public static void TestCars1()

    {

        Console.WriteLine("\nTestCars1");

        Console.WriteLine(line);

        Car car1 = new Car();

        car1.DescribeCar();

        // Notice the output from this test case. The new modifier is used in the definition of ShowDetails in the ConvertibleCar class.  

        Convertible car2 = new Convertible();

        car2.DescribeCar();

        Minivan car3 = new Minivan();

        car3.DescribeCar();

        Console.WriteLine(line);

    }

    public static void TestCars2()

    {

        Console.WriteLine("\nTestCars2");

        Console.WriteLine(line);

        var cars = new List<Car> { new Car(), new Convertible(), new Minivan() };

        foreach (var car in cars)

        {

            car.DescribeCar();

        }

        Console.WriteLine(line);

    }

    public static void TestCars3()

    {

        Console.WriteLine("\nTestCars3");

        Console.WriteLine(line);

        Convertible car2 = new Convertible();

        car2.ShowDetails();

        Minivan car3 = new Minivan();

        car3.ShowDetails();

        Console.WriteLine(line);

    }

    public static void TestCars4()

    {

        Console.WriteLine("\nTestCars4");

        Console.WriteLine(line);

        Car car2 = new Convertible();

        car2.ShowDetails();

        Car car3 = new Minivan();

        car3.ShowDetails();

        Console.WriteLine(line);

    }

}