Exercise: Constructors Static and ReadOnly

Constructors

1. Add a constructor to the Car class.
2. Initialize the value of all the variables.
3. In the TestClass add one more car instance.
4. Call the CarInfo method of the new car.
5. Build and Test.

Your Car class supposed to look like this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Northwind.Exercises.MoreOnClass
{
    class Car
    {
        public string carName;
        public int carYear;
        public int CarKM;
        public string carType;
        public Car()
        {
            carName = "No name given";
            carYear = 0;
            CarKM = 0;
            carType = "No type given";
        }
        public void CarInfo()
        {
            MessageBox.Show("My " + this.carType + " car is " + this.carYear + " " + this.carName + "\n" +
                " I drove it for " + this.CarKM + " KM");
        }
    }
} 

Your TestClass class supposed to look like this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Northwind.Exercises.MoreOnClass
{
    class TestClass
    {
        public void Run()
        {
            Car mainCar = new Car();
            Car weekendCar = new Car();
            Car funCar = new Car();

            mainCar.carName = "BMW X6";
            mainCar.carYear = 2015;
            mainCar.CarKM = 20000;
            mainCar.carType = "Main";

            weekendCar.carName = "Ford mustang";
            weekendCar.carYear = 1965;
            weekendCar.CarKM = 160000;
            weekendCar.carType = "Weekend";

            mainCar.CarInfo();
            weekendCar.CarInfo();
            funCar.CarInfo();
        } 

Static

1. In the Car class:
   1. Add static variable type int name it CarCounter.
   2. Add variable type int name it Id.
2. In the class constructor:
   1. Set the CarCounter to increase by one.
   2. In the Class constructor set the Id value to the value of the CarCounter.
3. Change the CarInfo method to reflect the new Id in the message box.
4. Build and Test

Your Car class supposed to look like this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Northwind.Exercises.MoreOnClass
{
    class Car
    {
        public string carName;
        public int carYear;
        public int CarKM;
        public string carType;
        static int CarCounter=0;
        public int Id;

        public Car()
        {
            CarCounter++;
            Id = CarCounter;
            carName = "No name given";
            carYear = 0;
            CarKM = 0;
            carType = "No type given";
        }
        public void CarInfo()
        {
-           MessageBox.Show("My " + this.carType + " car is " + this.carYear + " " + this.carName + "\n" +
-               " I drove it for " + this.CarKM + " KM");
            MessageBox.Show("My number"+ this.Id + " " + this.carType + " car is " + this.carYear + " " + this.carName + "\n" +
                " I drove it for " + this.CarKM + " KM");
        }
    }
} 

ReadOnly

1. In the TestClass class Try to update the Id of one of the cars to 10.
2. Build and test.
3. In the car class change the Id variable to readonly.
4. Notice the error message in the TestClass class.
5. Delete the update of the Id from the TestClass.
6. Build and test.

Your Car class supposed to look like this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Northwind.Exercises.MoreOnClass
{
    class Car
    {
        public string carName;
        public int carYear;
        public int CarKM;
        public string carType;
        static int CarCounter=0;
        public readonly int Id;

        public Car()
        {
            CarCounter++;
            Id = CarCounter;
            carName = "No name given";
            carYear = 0;
            CarKM = 0;
            carType = "No type given";
        }
        public void CarInfo()
        {
            MessageBox.Show("My number"+ this.Id + " " + this.carType + " car is " + this.carYear + " " + this.carName + "\n" +
                " I drove it for " + this.CarKM + " KM");
        }
    }
} 

Your TestClass class supposed to look like this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Northwind.Exercises.MoreOnClass
{
    class TestClass
    {
        public void Run()
        {
            Car mainCar = new Car();
            Car weekendCar = new Car();
            Car funCar = new Car();

            mainCar.carName = "BMW X6";
            mainCar.carYear = 2015;
            mainCar.CarKM = 20000;
            mainCar.carType = "Main";

            weekendCar.carName = "Ford mustang";
            weekendCar.carYear = 1965;
            weekendCar.CarKM = 160000;
            weekendCar.carType = "Weekend";

-           mainCar.Id = 10;
            mainCar.CarInfo();
            weekendCar.CarInfo();
            funCar.CarInfo();
        }
    }
} 

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