class Book extends Article {
  
  // additional Attributes
  String author, title, publisher;
  int year;
  
  // Methods
  void showInfo() {
    super.showInfo(); // article show info
    System.out.println ("Type:\tBook");
    System.out.println ("Author:\t"+author);
    System.out.println ("Title:\t"+title);
    System.out.println ("publisher:\t"+publisher);
    System.out.println ("year:\t"+year);
  }
  
  // Constructor
  Book (int code, String author, String title, int price)  { 
    super(code, author+": "+title, price); // use article constructor
    this.author = author;
    this.title = title;
    this.publisher = ""; // can be used later
    this.year = 0; // later
  } 

}