Question

Concepts: Classes, Objects, Inheritance, Method overriding (toString), polymorphic methods, Array of objects, loops

1. (Classes and Objects) Hand-write a complete Java class that can be used to create a Car object as described below.

a. A Vehicle has-a: i. Registration number ii. Owner name iii. Price iv. Year manufactured

b. Add all instance variables

c. The class must have getters and setters for all instance variables

d. The class must have two constructors, a no-args and a constructor that receives input parameters for each instance variable.

2. (Inheritance) Hand-write two Java classes, Car and Truck. They are both subclasses of Vehicle.

a. A car has an additional instance variable, number of doors.

b. A truck has an additional instance variable, number of axles

c. Write a constructor that requires input for the instance variables of each class (including registration number and owner name).

d. Write getters and setters for all instance variables for both classes.

3. (Array of objects) The array of Vehicles below, write the static method, findMin which returns the lowest price of any Vehicle in the Array Vehicle [] myVehicles = new Vehicle[10]; public static double findMin(Vehicle [] theVehicles) { }

4.Write a class, TestVehicle, which does the following: 1. Creates one Car object from information entered by the user. 2. Creates one Truck object from information entered by the user. 3. Creates an Array of Vehicles that can hold 10 objects. 4. It creates up to 10 Vehicles objects from information entered by the user 5. Prints the information about each object in the format shown below using the toString methods of the classes

*****PLEASE USE THE CODE BELOW I HAVE SO FAR TO COMPLETE THE PROGRAM****

****************************************************************************************

public class Vehicle {
   //Instance Variables
       private int registrationNumber;
       private String ownerName;
       private double price;
       private int yearManufactured;
   //Constructors
       public Vehicle (){
           this.registrationNumber=0;
           this.ownerName= " ";
           this.price=0;
           this.yearManufactured=0;
          
       }
       public Vehicle (int newRegisteration, String newName, double newPrice, int newMnf) {
           this.registrationNumber = newRegisteration;
           this.ownerName = newName;
           this.price = newPrice;
           this.yearManufactured = newMnf;
       }
   //Get methods
       public int getRegistration () {
           return this.registrationNumber;
           }

           public String getName () {
           return this.ownerName;
           }

           public double getPrice () {
           return this.price;
           }

           public int getYearManufactured () {
           return this.yearManufactured;
           }
           //Mutators or Setters
           public void setRegistration (int newRegistration) {
               this.registrationNumber=newRegistration;
           }

           public void setName (String newName) {
               this.ownerName=newName;
           }
           public void setPrice (double newPrice) {
               this.price=newPrice;
           }

           public void setYearManufactured (int newYearManufactured) {
               this.yearManufactured=newYearManufactured;
           }
       public String toString () {
           return " Vehicle: \nRegistration Number: " +registrationNumber
                   + " Owner Name: "+ownerName+ " Price: "+price+ " Year Manufactured: " +yearManufactured;
       }
      
   }//end of class

**********************************************************************************************

public class Car extends Vehicle {
//Instance Variables
   private int numOfDoors;
   //Constructors
  
public Car() {
   super();
}

}//end of class

Answer 1

CODE IN JAVA:

Vechicle.java file:

public class Vehicle {
   // Instance Variables
   private int registrationNumber;
   private String ownerName;
   private double price;
   private int yearManufactured;

   // Constructors
   public Vehicle() {
       this.registrationNumber = 0;
       this.ownerName = " ";
       this.price = 0;
       this.yearManufactured = 0;

   }

   public Vehicle(int newRegisteration, String newName, double newPrice, int newMnf) {
       this.registrationNumber = newRegisteration;
       this.ownerName = newName;
       this.price = newPrice;
       this.yearManufactured = newMnf;
   }

   // Get methods
   public int getRegistration() {
       return this.registrationNumber;
   }

   public String getName() {
       return this.ownerName;
   }

   public double getPrice() {
       return this.price;
   }

   public int getYearManufactured() {
       return this.yearManufactured;
   }

   // Mutators or Setters
   public void setRegistration(int newRegistration) {
       this.registrationNumber = newRegistration;
   }

   public void setName(String newName) {
       this.ownerName = newName;
   }

   public void setPrice(double newPrice) {
       this.price = newPrice;
   }

   public void setYearManufactured(int newYearManufactured) {
       this.yearManufactured = newYearManufactured;
   }

   public String toString() {
       return " Vehicle: \nRegistration Number: " + registrationNumber + " Owner Name: " + ownerName + " Price: " + price + " Year Manufactured: " + yearManufactured;
   }
   public static double findMin(Vehicle[] theVehicles) {
       int n = theVehicles.length;
       double low = theVehicles[0].getPrice();
       for(int i=1;i<n;i++) {
           if(theVehicles[i].getPrice()<low)
               low = theVehicles[i].getPrice();
       }
       return low;
   }

}

Car.java file:

public class Car extends Vehicle {
//Instance Variables
   private int numOfDoors;
   // Constructors

   public Car(int newRegisteration, String newName, double newPrice, int newMnf,int numOfDoors) {
       super(newRegisteration,newName,newPrice,newMnf);
       this.numOfDoors = numOfDoors;
   }

   public String toString() {
       return " Car: \nRegistration Number: " + this.getRegistration() + " Owner Name: " + this.getName() + " Price: " + getPrice() + " Year Manufactured: " + getYearManufactured()+" numOfDoors=" + numOfDoors ;
   }

   public int getNumOfDoors() {
       return numOfDoors;
   }

   public void setNumOfDoors(int numOfDoors) {
       this.numOfDoors = numOfDoors;
   }
  

}

Truck.java file:

public class Truck extends Vehicle{
   private int numOfAxles;
   Truck(int newRegisteration, String newName, double newPrice, int newMnf,int numOfAxles){
       super(newRegisteration,newName,newPrice,newMnf);
       this.numOfAxles = numOfAxles;
   }
   public int getNumOfAxles() {
       return numOfAxles;
   }

   public void setNumOfAxles(int numOfAxles) {
       this.numOfAxles = numOfAxles;
   }
   public String toString() {
       return " Truck: \nRegistration Number: " + this.getRegistration() + " Owner Name: " + this.getName() + " Price: " + getPrice() + " Year Manufactured: " + getYearManufactured()+" numberOfAxles=" + numOfAxles ;
   }
}
TestVehicle.java file:

import java.util.Scanner;

public class TestVehicle {

   public static void main(String[] args) {
       int registrationNumber;
       String ownerName;
       double price;
       int yearManufactured;
       int numOfDoors;
       int numOfAxles;
       Scanner sc = new Scanner(System.in);
       System.out.print("Enter Registratin number:");
       registrationNumber = sc.nextInt();
       System.out.print("Enter Owner name :");
       ownerName = sc.nextLine();
       ownerName = sc.nextLine();
       System.out.print("Enter price:");
       price = sc.nextDouble();
       System.out.print("Enter year manfactured:");
       yearManufactured = sc.nextInt();
       System.out.print("Enter number of doors:");
       numOfDoors = sc.nextInt();
       Car c = new Car(registrationNumber, ownerName, price, yearManufactured, numOfDoors);
       System.out.print("Enter Registratin number:");
       registrationNumber = sc.nextInt();
       System.out.print("Enter Owner name :");
       ownerName = sc.nextLine();
       ownerName = sc.nextLine();
       System.out.print("Enter price:");
       price = sc.nextDouble();
       System.out.print("Enter year manfactured:");
       yearManufactured = sc.nextInt();
       System.out.print("Enter number of axles:");
       numOfAxles = sc.nextInt();
       Truck t = new Truck(registrationNumber, ownerName, price, yearManufactured, numOfAxles);
       System.out.println(c);
       System.out.println();
       System.out.println(t);
       System.out.println();
       Vehicle v[] = new Vehicle[10];
       for (int i = 0; i < 10; i++) {
           System.out.println("Enter vehicle information:");
           System.out.print("Enter Registratin number:");
           registrationNumber = sc.nextInt();
           System.out.print("Enter Owner name :");
           ownerName = sc.nextLine();
           ownerName = sc.nextLine();
           System.out.print("Enter price:");
           price = sc.nextDouble();
           System.out.print("Enter year manfactured:");
           yearManufactured = sc.nextInt();
           Vehicle vh = new Vehicle(registrationNumber, ownerName, price, yearManufactured);
           v[i] = vh;
       }
       System.out.println("Below is all 10 vehicles information:");
       for (int i = 0; i < 10; i++)
           System.out.println(v[i]);

   }

}

OUTPUT: