Practice_Online_Library.java

package com.company;

class Library
{

    int no_of_books;
    String[] books;

    public Library() {
        this.books=new String[100];
        this.no_of_books=0;
    }

    void addBook(String book){
        this.books[no_of_books] = book;
        no_of_books++;
        System.out.println(book+ " has been added!");
    }

    void showAvailableBooks(){
        System.out.println("Available Books are:");
        for (String book : this.books) {
            if (book == null){
                continue;
            }
            System.out.println("* " + book);
        }
    }

    void issueBook(String book){
        for (int i=0;i<this.books.length;i++){
            if (this.books[i].equals(book)){
                System.out.println("The book has been issued!");
                this.books[i] = null;
                return;
            }
        }
        System.out.println("This book does not exist");
    }

    void returnBook(String book){
        addBook(book);
    }

}
public class Practice_Online_Library {
    public static void main(String[] args) {
        // You have to implement a library using Java Class "Library"
        // Methods: addBook, issueBook, returnBook, showAvailableBooks
        // Properties: Array to store the available books,
        // Array to store the issued books

        Library l1=new Library();
        l1.addBook("C++");
        l1.addBook("Java");
        l1.addBook("Python");


        l1.issueBook("C++");
        l1.returnBook("C++");
        l1.showAvailableBooks();
    }
}