Day 13: Abstract Classes HackerRank Solution

Day 13: Abstract Classes HackerRank Solution
Source : https://www.hackerrank.com/challenges/30-abstract-classes

Objective
Today, we're taking what we learned yesterday about Inheritance and extending it to Abstract Classes. Because this is a very specific Object-Oriented concept, submissions are limited to the few languages that use this construct. Check out the Tutorial tab for learning materials and an instructional video!

Task
Given a Book class and a Solution class, write a MyBook class that does the following:

• Inherits from Book
• Has a parameterized constructor taking these parameters:
  1. string
  2. string
  3. int
• Implements the Book class' abstract display() method so it prints these lines:
  1. , a space, and then the current instance's .
  2. , a space, and then the current instance's .
  3. , a space, and then the current instance's .

Note: Because these classes are being written in the same file, you must not use an access modifier (e.g.: ) when declaring MyBook or your code will not execute.

Input Format

You are not responsible for reading any input from stdin. The Solution class creates a Book object and calls the MyBook class constructor (passing it the necessary arguments). It then calls the display method on the Book object.

Output Format

The method should print and label the respective , , and of the MyBook object's instance (with each value on its own line) like so:

Title: $titleAuthor: $authorPrice: $price

Note: The is prepended to variable names to indicate they are placeholders for variables.

Sample Input

The following input from stdin is handled by the locked stub code in your editor:

The AlchemistPaulo Coelho248

Sample Output

The following output is printed by your display() method:

Title: The AlchemistAuthor: Paulo CoelhoPrice: 248

Source : https://www.hackerrank.com/challenges/30-abstract-classes

Solution

	// Karthikalapati.blogspot.com
	import java.util.*;
	abstract class Book {
	String title;
	String author;
	Book(String t, String a) {
	title = t;
	author = a;
	}
	abstract void display();
	}
	class MyBook extends Book {
	int price;
	MyBook(String title, String author, int price) {
	super(title, author);
	this.price = price;
	}
	void display() {
	System.out.println("Title: " + title);
	System.out.println("Author: " + author);
	System.out.println("Price: " + price);
	}
	}
	public class Solution {
	public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	String title = sc.nextLine();
	String author = sc.nextLine();
	int price = sc.nextInt();
	Book new_novel = new MyBook(title, author, price);
	new_novel.display();
	}
	}