Java OOP How to get user input for variables

Question

First of all, I am sorry if it's hard to understand me as I am not native English speaker my point might be hard to understand.

I am trying to make a very basic library booking system, but I have a problem with getting user input to adjust book details.

What I am trying to do is to get the book details from user input, but I don't know how to do this properly. I tried the same style that I use to change status but it doesn't seem to work.

I am also having some difficulties with checking and changing the books status from available to booked.

This is the main program:

public static void main(String[] args) {

    System.out.println("Welcome to the basic library program! ");
    System.out.println("Insert author, name, genre, ISNB, page number ");

    // this one is wrong.
    Book booking = new Book("Mary","Random Book","Horror",69,69);

    System.out.println("Print book information? 1 = yes 2 = no?");
    int answer = input.nextInt();
    if (answer == 1) {
        booking.printBook();
    }
    else {

    }

    System.out.println("Check books status? 1= yes 2= no");
    int status = input.nextInt();
    if (status == 1) {
        booking.checkStatus(); 
    }
    else {

    }

    System.out.println("Change books status: 1 = Avaible 2 = Booked 3 = Lost ");
    int availability = input.nextInt();
    booking.changeAvailability(availability);
}

And this is the book class:

public class Book {

    private String author;
    private String name;
    private String genre;
    private int isbn;
    private int pageNumber;
    private int availability;
    private String setAvailability;

    public Book(String authorInput, String nameInput, String genreInput, int isbnInput, int pageInput) {

        this.author = authorInput;
        this.name = nameInput;
        this.genre = genreInput;
        this.isbn = isbnInput;
        this.pageNumber = pageInput;

    }



    public void changeAvailability(int availability) {  
        if (availability == 1) {
            setAvailability = "Avaible";
            System.out.println("Avaible.");
        }
        else if (availability == 2) {
            setAvailability = "Not avaible";
            System.out.println("Not avaible.");         
            }
        else if (availability == 3) {
            setAvailability = "Lost";
            System.out.println("Book missing.");
        }
        else {
               System.out.println("Unknown input: Program closing..");
               System.exit(1);
           }

    }

    public String checkStatus() {
        return this.setAvailability;
    }

    public void printBook() {

        System.out.print("Author: " + this.author + "\nName: " + this.name + "\nGenre: " + this.genre + "\nISBN: " + this.isbn + "\nPages: " + this.pageNumber + "\nAvailability:" + " ");

        }
    }

Answer 1

You need to use a Scanner in your main() class. For example in your code:

Scanner input = new Scanner (System.in);

needs to be entered before you try to get the user's input. This will allow you to call input.nextInt(); successfully.

See a previous question here: How can I get the user input in Java?

Answer 2

As the first answer said you needed to use a Scanner. All you had to do was pass the scanner variables into the book created object directly. Your logic was a slightly off on a couple things and I have had way too much time on my hands tonight so I just redid your problem my way.

import java.util.Scanner;

public class bookTest {

public static void main(String[] args) {


    Scanner input = new Scanner(System.in);


    System.out.println("Welcome to the basic library program! ");
    System.out.println("Insert author, name, genre, ISNB, page number ");
    String author = input.next();
    String name = input.next();
    String genre = input.next();
    int isbn = input.nextInt();
    int pageNumber = input.nextInt();


    Book booking = new Book(author,name ,genre,isbn,pageNumber);


    System.out.println("Change books status: 1 = Avaible 2 = Booked 3 = Lost ");
    int availability = input.nextInt();
    booking.changeAvailability(availability);


    System.out.println("Print book information? 1 = yes 2 = no?");
    int answer = input.nextInt();
    if (answer == 1) {
        booking.printBook();
    }


    System.out.println("Check book status? 1= yes 2 = no");
    int status = input.nextInt();
    if (status == 1) {
       booking.checkStatus(); 
    }




}



}

Next is the Book class redid

public class Book {

private String author;
private String name;
private String genre;
private int isbn;
private int pageNumber;
private int availability;


       public Book(String authorInput, String nameInput, String genreInput, int       isbnInput, int pageInput) {
       this.author = authorInput;
       this.name = nameInput;
       this.genre = genreInput;
       this.isbn = isbnInput;
       this.pageNumber = pageInput;

   }

public void changeAvailability(int setAvailability) {  
       if (setAvailability == 1) {
           availability = 1;
       }
       else if (setAvailability == 2) {
           availability = 2;
           }
       else if (setAvailability == 3) {
           availability = 3;
       }
       else {
              System.out.println("Unknown input: Program closing..");
              System.exit(1);
          }

   }

    //Instead of set use get
   public void checkStatus() {
       if (availability == 1) {
           System.out.println("Avaible.");
       }
       else if (availability == 2) {
           System.out.println("Not avaible.");         
           }
       else if (availability == 3) {
           System.out.println("Book missing.");
       }
       else {
              System.out.println("Unknown input: Program closing..");
              System.exit(1);
          }    
   }

   public void printBook() {

       System.out.println("Author: " + this.author + "\nName: " + this.name + "\nGenre: " + this.genre + "\nISBN: " + this.isbn + "\nPages: " + this.pageNumber);

       }
}