using System;

public class Program

{

    public static void Main()

    {

        Coupe coupe = new Coupe();

        Truck truck = new Truck(10);

    }

    public class Car

    {

        protected int wheels;

        public Car()

        { 

            wheels = 4; 

        }

    }

​

    public class Coupe : Car

    {

        public Coupe()//:base()       

        {

            Console.WriteLine("Coupe" + wheels.ToString()); 

        }

    }

​

    public class Truck : Car

    {

        public Truck(int wheels)//:base()

        {

            wheels = wheels;

            Console.WriteLine("Truck: " + wheels.ToString());

        }

    }

}