/* Thursday am lecture - Part 4:

            +--------+                
            | LoBook |<--------------+
            +--------+               |
            +--------+               |
                 |                   |
                / \                  |
                ---                  |
                 |                   |
       -------------------           |
       |                 |           |
  +----------+    +-------------+    |
  | MTLoBook |    | ConsLoBook  |    |
  +----------+    +-------------+    |
  +----------+  +-| Book first  |    |
                | | LoBook rest |-+  |
                | +-------------+ |  |
                |                 |  |
                v                 +--+
       +---------------+
       | Book          |
       +---------------+
       | String title  |
       | String author |
       | Num cnum      |
       +---------------+
*/

// to represent a book in a library
class Book{
  String title;
  String author;
  int cnum;

  Book(String title, String author, int cnum){
    this.title = title;
    this.author = author; 
    this.cnum = cnum;
  }
}


// to represent a list of books
interface LoBook {
}

// to represent an empty list of books
class MTLoBook implements LoBook {

  MTLoBook() {
  }
}

// to represent a nonempty list of books
class ConsLoBook implements LoBook {
  Book first;
  LoBook rest;

  ConsLoBook(Book first, LoBook rest) {
    this.first = first;
    this.rest = rest;
  }
}

// client class for a list of books
class Examples3{
  Examples3(){}

  Book ch = new Book("Cat in a Hat", "Dr Seuss", 777);
  Book alice = new Book("Alice's Adventures in Wonderland", "Lewis Carroll", 234);
  Book geh = new Book("Green Eggs and Ham", "Dr Seuss", 779);

  LoBook mtbks = new MTLoBook();
  LoBook lobks1 = new ConsLoBook(this.ch, this.mtbks);
  LoBook lobks2 = new ConsLoBook(this.alice, this.lobks1);
  LoBook lobks3 = new ConsLoBook(this.geh, this.lobks2);
}