package lecture5.objects; import java.util.ArrayList; public class Library { ArrayList<Book> books; public Library(){ books = new ArrayList<Book>(); } void add(Book book){ books.add(book); } boolean hasBook(Book book){ return books.contains(book); } public static void main(String[] args){ Library myBooks = new Library(); System.out.println(myBooks.books); myBooks.add(new Book("Hvordan være tøff", "Anders")); System.out.println(myBooks.books); Book myFavorite = new Book("INF101", "Sondre"); System.out.println(myBooks.hasBook(myFavorite)); myBooks.add(myFavorite); System.out.println(myBooks.hasBook(myFavorite)); System.out.println(myBooks.books); Book wanted = new Book("Hvordan være tøff", "Anders"); System.out.println(myBooks.hasBook(wanted)); } }