public static void main(String[] args) {
        while (true) {
            displayMenu();

            int userChoice = 0;
            try {
                String value = getUserInput("Your Selection: ");
                userChoice = Integer.parseInt(value);
            } catch (Exception e) {
                System.out.println("Enter a valid integer!!");
            }

            if (userChoice == 1) {
                displayBooks();
            } else if (userChoice == 2) {
                checkOutBooks();
            } else if (userChoice == 3) {
                if (loggedIn()) {
                    System.out.println("\nYour library number is " + savedLibraryNumber);
                } else {
                    System.out.println("\nPlease talk to Librarian. Thank you.");
                }
            } else if (userChoice == 4) {
                displayMovies();
            } else if (userChoice == 5) {
                clearLogin();
                login();
            } else if (userChoice == 9) {
                System.out.println("Quitting...");
                break;
            } else {
                System.out.println("\nEnter a valid integer!!");
            }
        }
    }