A Java program to show the use constructor in java

This program is implemented by Naman Dhiman from NIT Uttrakhand

import java.util.Scanner;

public class Book {

// non static data members

int id;

String topic;

String author;

float price;

String publisher;

// no argument constructor of Book

public Book()

{

                // initializing the data members 

id = 101;

topic = "Let Us C";

author = "Kanethkar";

price = 350.2f;

publisher = "Macmillan";

}

// parameterized constructor of Book  

  public Book(int id, String topic, String author, float price, String publisher) {

                // initializing the data members 

               // this.id means non static variable while id is a local variable

this.id = id;

this.topic = topic;

this.author = author;

this.price = price;

this.publisher = publisher;

}

// non static method to show data of Book 

    void info()

    {

    System.out.println("ID = "+id);

    System.out.println("Topic = "+topic);

    System.out.println("Author = "+author);

    System.out.println("Price = "+price);

    System.out.println("Publisher = "+publisher);

    }

public static void main(String[] args) {

// create object of Book using no argument constructor

Book b1 = new Book();

// show info of Book

b1.info();

// create object of Book using parameterized constructor

Book b2 = new Book(102,"Concepts in Java","Herbert Schildt",800.5f,"PHI");

// show info of Book

b2.info();

// create object of Book using parameterized constructor

Book b3 = new Book(103,"C","E.Balaguruswamy",400.75f,"Hachette");

// show info of Book

b3.info();

// object of Scanner to take input from keyboard

Scanner sc = new Scanner(System.in);

// take some inputs

System.out.println("Enter Book id");

int id = sc.nextInt();

System.out.println("Enter book topic");

String topic = sc.next();

System.out.println("Enter Author's Name");

String author = sc.next();

System.out.println("Enter Price");

float price = sc.nextFloat();

System.out.println("Enter Publisher's Name");

String publisher = sc.next();

// create object of Book using parameterized constructor

// here we are passing variable names as arguments

Book b4 = new Book(id,topic,author,price,publisher);

// show info of Book

b4.info();

}

}