Question

Write 3 Java classes called Car, OffroadCar and HybridCar. Demonstrate the concept of inheritance by making the Car class your superclass. Give it the following attributes:

int num_doors; // number of doors the car has

int hp; // the horse power of the car

boolean manual; // true if manual transmission, false if automatic

____________

OffroadCar Class

should be derived from the Car class and have the additional attribute:

int wheel_diameter; // diameter of wheel in mm.

_____________________

HybridCar

should be derived from the Car class and have the additional attribute:

int batteries; // number of batteries in the car

Answer 1

//Java code

/**
 * Class Car
 */
public class Car {
/**
 * Attributes
 *
 */
private int num_doors; // number of doors the car has

   private int hp; // the horse power of the car
    private boolean manual; // true if manual transmission, false if automatic

    /**
     * Constructor
     */
    public Car(int num_doors, int hp, boolean manual) {
        this.num_doors = num_doors;
        this.hp = hp;
        this.manual = manual;
    }
    //getters and setters

    public int getNum_doors() {
        return num_doors;
    }

    public void setNum_doors(int num_doors) {
        this.num_doors = num_doors;
    }

    public int getHp() {
        return hp;
    }

    public void setHp(int hp) {
        this.hp = hp;
    }

    public boolean isManual() {
        return manual;
    }

    public void setManual(boolean manual) {
        this.manual = manual;
    }

    /**
     * @return string format of Object Car
     */
    @Override
    public String toString() {
        return "Number of doors: "+num_doors+"\nHorse power of car: "+hp+" hp"+
                "\nIs Manual Transmission: "+manual;
    }
}

============================================================

/**
 * OffroadCar Class
 */
public class OffroadCar extends Car {
    private int wheel_diameter; // diameter of wheel in mm.

    public OffroadCar(int num_doors, int hp, boolean manual, int wheel_diameter) {
        /**
         * super keyword call the super class constructor
         * in this case Car
         */
        super(num_doors, hp, manual);
        this.wheel_diameter = wheel_diameter;
    }

    public int getWheel_diameter() {
        return wheel_diameter;
    }

    public void setWheel_diameter(int wheel_diameter) {
        this.wheel_diameter = wheel_diameter;
    }

    @Override
    public String toString() {
        System.out.println("=============================================");
        return super.toString()+"\nWheel diameter: "+wheel_diameter+" mm"
                +"\n=============================================\n";
    }
}

=============================================================================

public class HybridCar extends Car {
    private int batteries; // number of batteries in the car

    public HybridCar(int num_doors, int hp, boolean manual, int batteries) {
        super(num_doors, hp, manual);
        this.batteries = batteries;
    }
    //getters and setters

    public int getBatteries() {
        return batteries;
    }

    public void setBatteries(int batteries) {
        this.batteries = batteries;
    }

    @Override
    public String toString() {
        System.out.println("=============================================");
        return super.toString()+"\nNumber of batteries: "+batteries
                +"\n=============================================\n";
    }
}

================================================================

public class TestCar {
    public static void main(String[] args)
    {
        HybridCar hybridCar = new HybridCar(4,300,true,20);
        OffroadCar offroadCar= new OffroadCar(2,450,true,4);
        //printinfo
        System.out.println(hybridCar);
        System.out.println(offroadCar);
    }
}

//output

//if you need any help regarding this solution ............ please leave a comment .......... thanks.......