Question

• Choose any entity of your choice to represent a superclass. It must not be any of the following:

- Human, Student, Vehicle, Person, Car, Animal

• Create a class for your entity with the following: - 3 instance variables - 3 instance methods - 2 of the instance methods must show overloading - A default constructor - A parameterized constructor that initializes all instance variables - Getters and setters for the instance variables - Method to print all the details for the class objects with captions for the data.

java language

• Create 2 subclasses for the superclass

• Each subclass must have the following: - 2 instance variables - A constructor that first initializes its object variables using the superclass constructor, then initializes the rest. - Getters and setters - A method that overrides the print method in the superclass

• Create a test class and test the print methods in all the classes.

Answer 1

Question:

• Choose any entity of your choice to represent a superclass. It must not be any of the following:

- Human, Student, Vehicle, Person, Car, Animal

• Create a class for your entity with the following: - 3 instance variables - 3 instance methods - 2 of the instance methods must show overloading - A default constructor - A parameterized constructor that initializes all instance variables - Getters and setters for the instance variables - Method to print all the details for the class objects with captions for the data.

java language

• Create 2 subclasses for the superclass

• Each subclass must have the following: - 2 instance variables - A constructor that first initializes its object variables using the superclass constructor, then initializes the rest. - Getters and setters - A method that overrides the print method in the superclass

• Create a test class and test the print methods in all the classes.

Answer:

import java.io.*;
import java.lang.*;

class Book
{
   //instance variables
   String name;
   String author_name;
   double price;
  
   //default constructor
   Book()
   {
       System.out.println("Default constructor called");
   }
  
   //parameterized constructor to initialize all instance variables
   public Book(String name, String author_name, double price)
   {
       this.name=name;
       this.author_name=author_name;
       this.price=price;
   }
  
   //instance methods
   public void story_book(String genre)   
   {
       System.out.println("This is "+genre+" type story book");
   }
  
   public void story_book(String genre, int upper_age_limit) //method overloading
   {
       System.out.println("This is "+genre+" type story book for upto "+upper_age_limit+" years");
   }
  
   public void print_book_details()
   {
       System.out.println("Name of the book: "+name);
       System.out.println("Author of the book: "+author_name);
       System.out.println("Price of the book: "+price+" USD");
   }
  
   // Getters and Setters
   // Returns the name of this book
   public String getName() {
       return name;
   }

   // Returns the name of the author of this book
   public String getAuthor() {
       return author_name;
   }
  
   // Returns the price of this book
   public double getPrice() {
       return price;
   }
  
   // Sets the price of this book
   public void setPrice(double price) {
       this.price = price;
   }
  
}

class Fiction_book extends Book
{
   //instance variables
   int discount_rate;
   String language;
  
   //parameterized constructor
   Fiction_book(String name, String author_name, double price, int discount_rate, String language)
   {
       super(name,author_name,price); //initailizing the superclass objects
       this.discount_rate=discount_rate;
       this.language=language;
   }
  
   //Getters and setters
   // Returns the language of this book
   public String getLanguage() {
       return language;
   }
  
   // Returns the discount rate of this book
   public int getDiscountRate() {
       return discount_rate;
   }
  
   // Sets the discount rate of this book
   public void setDiscountRate(int discount_rate) {
       this.discount_rate = discount_rate;
   }

   //Overriding the parent method
   @Override
   public void print_book_details()
   {
       System.out.println("Name of the book: "+name);
       System.out.println("Author of the book: "+author_name);
       System.out.println("Price of the book: "+price+" USD");
       System.out.println("Discount rate of the book: "+discount_rate);
       System.out.println("Language of the book: "+language);
   }
  
}

class Horror_book extends Book
{
   //instance variables
   int no_of_pages;
   int no_of_chapters;
  
   //parameterized constructor
   Horror_book(String name, String author_name, double price, int no_of_pages, int no_of_chapters)
   {
       super(name,author_name,price); //initailizing the superclass objects
       this.no_of_pages=no_of_pages;
       this.no_of_chapters=no_of_chapters;
   }
  
   //Getters and setters
   // Returns the language of this book
   public int getNoOfPages() {
       return no_of_pages;
   }
  
   // Returns the discount rate of this book
   public int getNoOfChapters() {
       return no_of_chapters;
   }
  
   // Sets the discount rate of this book
   public void setNoOfPages(int no_of_pages) {
       this.no_of_pages = no_of_pages;
   }

   //Overriding the parent method
   @Override
   public void print_book_details()
   {
       System.out.println("Name of the book: "+name);
       System.out.println("Author of the book: "+author_name);
       System.out.println("Price of the book: "+price+" USD");
       System.out.println("No. of pages in the book: "+no_of_pages);
       System.out.println("No. of chapters of the book: "+no_of_chapters);
   }
  
}

// Test class to test all the methods in all classes
class TestBook
{
   public static void main (String[] args)
   {
       //Test Book's constructor
       Book book1 = new Book("The Secret Seven","Enid Blyton",27.72);
      
       //For printing all details of the book
       book1.print_book_details();
      
       //Test setters and getters
       System.out.println("Book's name is: "+book1.getName());
       System.out.println("Book author's name is: "+book1.getAuthor());
       System.out.println("Book's price is: "+book1.getPrice()+" USD");
       book1.setPrice(25.42);
       System.out.println("Now, the book's price is: "+book1.getPrice()+" USD");
      
       //Test method overloading of instance methods
       book1.story_book("Children detective");
       book1.story_book("Children detective",18);
      
       System.out.println("---------------------------------------------------\n");
      
       //Test Fiction_book's constructor
       Fiction_book book2 = new Fiction_book("1984","George Orwell",25.84,10,"English");
  
       //For printing all details of the book (testing overriding of parent method)
       book2.print_book_details();
  
       //Test setters and getters
       System.out.println("Book's discount rate is: "+book2.getDiscountRate());
       System.out.println("Book's language is: "+book2.getLanguage());
       book2.setDiscountRate(15);
       System.out.println("Now, the book's discount rate is: "+book2.getDiscountRate());
      
       System.out.println("---------------------------------------------------\n");

       //Test Horror_book's constructor
       Horror_book book3 = new Horror_book("The Haunting of the Hill House","Shirley Jackson",14.50,700,15);
      
       //For printing all details of the book (testing overriding of parent method)
       book3.print_book_details();
      
       //Test setters and getters
       System.out.println("No. of pages in the book is: "+book3.getNoOfPages());
       System.out.println("No. of chapters in the book is: "+book3.getNoOfChapters());
       book3.setNoOfPages(600);
       System.out.println("Now, the no. of pages in the book is: "+book3.getNoOfPages());

   }

}