public class Book {
  
   // the constructor: this is called when you say ''new Book(...)''
   // it gets two Strings and an int as ''arguments''

   public Book(String t, String a, int y) {

      // the constructor assigns its arguments (it gow from ''new Book(...)''
      // to variables that belong to class Book

      title = t;
      author = a;
      year = y;
   }


   // here are these variables that belong to class Book, they are
   // ''private'', they cannot be used by any code outside class Book

   private String title;
   private String author;
   private int year;

   // some more private variables: we want to know if a book is lend out
   // and by whom, for a new Book objects, the default values are given

   private boolean available = true;
   private String user = null;


   // cool :)
   // now we need some methods!
   // people might want to know things about a Book object. Since
   // we keep our variables private, we need to provide ''methods''
   // for them to use!

   // note they don't get any arguments - the argument list is empty ()

   public String getTitle() {
       return title;
   }
   public String getAuthor() {
       return author;
   }

   public int getYear() {
       return year;
   }

   public String getUser() {
       return user;
   }

   public boolean isAvailable() {
       return available;
   }


   // and here come the lendTo() and giveBack() methods!

   // note they don't return anything (return value is declared to be void)

  public void lendTo(String u) {
       user = u;
       available = false;
  }

  public void giveBack() {
        user = null;
        available = true;
  }



}