using System;

public class Program

{

    public static void Main()

    {

        Car car = new Car ();

        Van van = new Van ("Ford", 2012);

        Vehicle vehicle = new Vehicle ("Nissan", "Sentra",2002);

        //Console.WriteLine(van);

        //Console.WriteLine(car.made);

    }

}

​

​

 //default constructor = no parameters

​

public class Car

{

    public string made;

    public Car ()

    {

        this.made = "Nissan Sentra 3";

    }

​

​

}

​

//with parameters. They prevent creating object with null values!

​

public class Van

{

​

    private string _make;

    private int _year;

    public Van (string make, int year)

    {

        this._make = make;

        this._year = year;

        Console.WriteLine("My van is {0} {1}" , make, year);

    }

​

}

​

public class Vehicle

{

    private string _make { get; set;}

    private string _model { get; set;}

    private int _year { get; set;}

    public Vehicle (string make, string model, int year)

    {

        this._make = make;

        this._model = model;

        this._year = year;

        Console.WriteLine("My vehicle is {0} {1} {2}", make, model, year);

    }

​

​

}