Question

re-implement the Bookshelf class using a linkedlist and a Node class. Implement the above add, remove, and search methods again.

here is the code for that:

public class Book {

  

private String title;

private double price;

  

public Book()

{

title="";

price=0;

}

  

public Book(String title, double price)

{

this.title = title;

this.price = price;

}

  

public void setTitle(String title)

{

this.title = title;

}

  

public void setPrice(double price)

{

this.price = price;

}

  

public String getTitle()

{

return title;

}

  

public double getPrice()

{

return price;

}

  

public boolean equals(Book book)

{

// if both title and price of both books are same

if((title.equalsIgnoreCase(book.title)) && (price == book.price))

return true;

return false;

}

  

public String toString()

{

return title+" : "+price;

}

}

//end of Book.java

//BookShelf.java : Java program to implement BookShelf using array

public class BookShelf {

  

private Book books[];

private int size;

  

public BookShelf(int capacity)

{

books = new Book[capacity];

size=0;

}

  

public int getSize()

{

return size;

}

  

public boolean addBook(Book book)

{

if(size < books.length)

{

books[size] = book;

size++;

return true;

}

return false;

}

  

public boolean removeBook(Book book)

{

for(int i=0;i<size;i++)

{

if(books[i].equals(book))

{

for(int j=i;j<size-1;j++)

books[j] = books[j+1];

size--;

return true;

}

}

  

return false;

}

  

public boolean searchBook(Book book)

{

for(int i=0;i<size;i++)

{

if(books[i].equals(book))

{

return true;

}

}

  

return false;

}

  

public String toString()

{

String booksStr = "";

for(int i=0;i<size;i++)

{

booksStr += books[i].toString()+"\n";

}

  

return booksStr;

}

public static void main(String args[])

{

BookShelf bookShelf = new BookShelf(10); // create a bookshelf object

// create 5 books and add them to bookshelf

Book book1 = new Book("Title1",20);

bookShelf.addBook(book1);

book1 = new Book("Title2",25);

bookShelf.addBook(book1);

book1 = new Book ("Title3",15);

bookShelf.addBook(book1);

book1 = new Book ("Title4",32.5);

bookShelf.addBook(book1);

book1 = new Book ("Title5",25);

bookShelf.addBook(book1);

  

System.out.println(bookShelf);

}

}

//end of BookShelf.java

Answer 1

/**
 * Please find the required solution
 */

// Node class with book and ref to second book
class Node {
    Book book;
    Node next;

    // constructor
    public Node(Book book) {
        this.book = book;
    }

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }
}

//BookShelf.java : Java program to implement BookShelf using LinkedList
public class BookShelf {

    private Node headNode;
    private int size;
    private int capacity;

    public BookShelf(int capacity) {
        this.capacity = capacity;
        size = 0;
    }

    public int getSize() {
        return size;
    }

    public boolean addBook(Book book) {
        if (size < capacity) {
            Node node = new Node(book);
            if (headNode == null)
                headNode = node;
            else {
                Node lastNode = headNode;
                while (lastNode.next != null) {
                    lastNode = lastNode.next;
                }
                lastNode.next = node;
            }
            size++;
            return true;
        }
        return false;
    }

    public boolean removeBook(Book book) {
        if (headNode.book.equals(book)) {
            headNode = headNode.next;
        }
        Node currNode = headNode, prev = null;
        while (currNode != null && currNode.book.equals(book)) {
            prev = currNode;
            currNode = currNode.next;
        }
        if (currNode != null) {
            prev.next = currNode.next;
            size--;
            return true;
        }
        return false;
    }

    public boolean searchBook(Book book) {

        Node lastNode = headNode;
        while (lastNode != null) {
            if (lastNode.book.equals(book))
                return true;
            lastNode = lastNode.next;
        }

        return false;
    }

    public String toString() {
        String booksStr = "";

        Node lastNode = headNode;
        while (lastNode != null) {
            booksStr += lastNode.book.toString() + "\n";
            lastNode = lastNode.next;
        }

        return booksStr;
    }

    public static void main(String args[]) {
        BookShelf bookShelf = new BookShelf(10); // create a bookshelf object
// create 5 books and add them to bookshelf
        Book book1 = new Book("Title1", 20);
        bookShelf.addBook(book1);
        book1 = new Book("Title2", 25);
        bookShelf.addBook(book1);
        book1 = new Book("Title3", 15);
        bookShelf.addBook(book1);
        book1 = new Book("Title4", 32.5);
        bookShelf.addBook(book1);
        book1 = new Book("Title5", 25);
        bookShelf.addBook(book1);

        System.out.println(bookShelf);
    }
}
//end of BookShelf.java 

Sample output:

Answer 2

// Linked List version of BookShelf
public class BookShelfLL {

    private Node head; // head of the BookShelf
    private int size; // Size of the BookShelf

    class Node {
        private Book data;
        private Node link;

        Node(Book book) {
            data = book;
            // link by default points to null
        }
    }

    public BookShelfLL() {
        head = null;
        size = 0;
    }

    public int getSize() {
        return size;
    }

    public boolean addBook(Book book) {

        Node newBook = new Node(book);

        if (newBook == null) {
            // Heap Overflow
            return false;
        }

        // Case : Linked List is Empty
        if (head == null) {
            head = newBook;
            size++;
        } else {
            // Traverse till the last node and add new Book there
            Node iterator = head;
            while (iterator.link != null) {
                iterator = iterator.link;
            }
            iterator.link = newBook;
            size++;
        }
        return true;
    }

    public boolean removeBook(Book book) {

        Node iterator = head;

        // Case A : The head is the book being searched
        if (iterator != null && iterator.data.equals(book)) {
            head = head.link;
            size--;
            return true;
        }

        // Case B : The book bein searched lies in a node other than head
        Node previous = null;
        while (iterator != null && !iterator.data.equals(book)) {
            previous = iterator;
            iterator = iterator.link;
        }


        // If the Book was present, it should be at iterator's current data
        // Therefore the iterator shall not be null
        if (iterator != null) {
            // Unlink the current Node
            previous.link = iterator.link;
            size--;
            return true;
        }

        // Case C : Book not present
        return false;
    }

    public boolean searchBook(Book book) {

        Node iterator = head;
        while (iterator != null && !iterator.data.equals(book)) {
            iterator = iterator.link;
        }

        // iterator will be null if Book not present
        return iterator != null;
    }

    public String toString() {
        String booksStr = "";
        Node iterator = head;
        while (iterator != null) {
            booksStr += iterator.data.toString() + "\n";
            iterator = iterator.link;
        }

        return booksStr;
    }

    public static void main(String args[]) {
        // Linked List version of BookShelf will have infinite capacity (The Limit of Heap)
        BookShelfLL bookShelf = new BookShelfLL(); // create a bookshelf object
        // create 5 books and add them to bookshelf
        Book book1 = new Book("Title1", 20);
        bookShelf.addBook(book1);
        Book book2 = new Book("Title2", 25);
        bookShelf.addBook(book2);
        book1 = new Book("Title3", 15);
        bookShelf.addBook(book1);
        book1 = new Book("Title4", 32.5);
        bookShelf.addBook(book1);
        book1 = new Book("Title5", 25);
        bookShelf.addBook(book1);

        System.out.println(bookShelf);

        // Remove Title2
        System.out.println(bookShelf.removeBook(book2));
        System.out.println("After removal");
        System.out.println(bookShelf);

        // Search Title5
        System.out.println(bookShelf.searchBook(book1));
    }
}