using System;

public class Program

{

    public static void Main()

    {

        // The important part of an abstract class is that you can never use it separately from a derived class. 

        // Therefore in Main you cannot use the new Vehicle() constructor.

        Car car = new Car();

        car.VehicleType = "Car";

        car.Driving();

        car.VehicleType = "Truck";

        car.Driving();

    }

    abstract class Vechicle

    {

        public string VehicleType;

        public abstract void Driving();

        public void Sound()

        {

            Console.WriteLine("Vechicle can make an sound");

        }

    }

    // When you create a derived class like Car or Truck, you must provide an override method for all abstract methods in the abstract class. 

    // The Driving() method in both derived classes satisfies this requirement.

    class Car : Vechicle

    {

        public override void Driving()

        {

            Console.WriteLine("Look im driving a {0}!", base.VehicleType);

        }

    }

    class Truck : Vechicle

    {

        public override void Driving()

        {

            Console.WriteLine("Look im driving a {0}!", base.VehicleType);

        }

    }

}