using System;
using System.Collections;
using System.Text;

//-------- Article -------

abstract class Article {
  int id;
  int price; // in Cent
  
  public Article(int id, int price) {
    this.id = id; this.price = price;
  }
  
  public int Id {
    get { return id; }
  }
  
  public int Price {
    get { return price; }
  }
  
  public abstract string Description();
  
}

//-------- Book -------

class Book : Article {
  string author;
  string title;
  string publisher;
  int year;
  
  public Book(int id, int price, string author, string title, string publisher, int year)
  : base(id, price) {
    this.author = author; this.title = title; this.publisher = publisher; this.year = year;
  }
  
  public override string Description() {
    return author + ": " + title + ". " + publisher + ", " + year;
  }
}

//-------- CD -------

class CD : Article {
  string singer;
  string title;
  ArrayList songs;
  
  public CD(int id, int price, string singer, string title) : base (id, price) {
    this.singer = singer; this.title = title; songs = new ArrayList();
  }
  
  public void AddSong(string song) {
    songs.Add(song);
  }
  
  public string Song(int i) {
    if (i < songs.Count) return (string)songs[i]; else return null;
  }
  
  public int NumberOfSongs {
    get { return songs.Count; }
  }
  
  public override string Description() {
    return singer + ": " + title;
  }
}

//-------- Video -------

class Video : Article {
  string title;
  int length;
  
  public Video(int id, int price, string title, int length) : base (id, price) {
    this.title = title; this.length = length;
  }
  
  public override string Description() {
    return title + ". " + length + " minutes";
  }
}

//-------- ShoppingCart -------

class ShoppingCart {
  ArrayList articles = new ArrayList();
  
  public void Add(Article a) {
    articles.Add(a);
  }
  
  public string Contents() {
    StringBuilder s = new StringBuilder();
    int total = 0;
    foreach (Article a in articles) {
      s.Append(String.Format("{0,6} ", a.Id));
      s.Append(String.Format("{0,7:f2} ", (float)a.Price / 100));
      s.Append(a.Description() + "\r\n");
      total += a.Price;
    }
    s.Append("--------------\r\n");
    s.Append(String.Format("       {0,7:f2}", (float)total / 100));
    return s.ToString();
  }
}

//-------- Shop -------

class Shop {
  Hashtable articles = new Hashtable();
  
  public void Add(Article a) {
    articles[a.Id] = a;
  }
  
  public Article Item(int id) {
    return (Article)articles[id];
  }
  
}

class Test {
  public static void Main() {
    Shop shop = new Shop();
    shop.Add(new Book(13544, 14999, "Donald Knuth", "The art of computer programming", "Addison-Wesley", 1999));
    shop.Add(new Book(15922, 1250, "Stephen Hawking", "A brief history of time", "Bantam", 1998));
    shop.Add(new Book(12768, 1190, "James Joyce", "Ulysses", "Vintage Books", 1990));
    shop.Add(new CD(24588, 3999, "John Coltrane", "Legacy"));
    shop.Add(new CD(27335, 11898, "Singers Unlimited", "Magic voices"));
    shop.Add(new CD(22766, 1198, "Lionell Hampton", "Ring them bells"));
    shop.Add(new Video(35682, 1754, "Harry Potter and the sorcerer's stone", 120));
    shop.Add(new Video(38577, 2249, "E.T.", 110));
    
    ShoppingCart cart = new ShoppingCart();
    cart.Add(shop.Item(27335));
    cart.Add(shop.Item(13544));
    cart.Add(shop.Item(35682));
    
    Console.WriteLine(cart.Contents());
  }
}