using System;
using System.Collections.Generic;

namespace IteratorsAndComparators
{
    public class StartUp
    {
        public static void Main()
        {
            Book bookOne = new Book("Animal Farm", 2003, "George Orwell");
            Book bookTwo = new Book("The Documents in the Case", 2002, "Dorothy Sayers", "Robert Eustace");
            Book bookThree = new Book("The Documents in the Case", 1930);

            Library libraryOne = new Library();
            Library libraryTwo = new Library(bookOne, bookTwo, bookThree);
        }
	}
	public class Book
    {
        public string Title { get; set; }
        public int Year { get; set; }
        public List<string> Authors { get; set; }
        public Book(string title,int year, params string[] authors)
        {
            this.Title = title;
            this.Year = year;
            this.Authors = authors.ToList();
        }
    }
	class Library : IEnumerable<Book>
    {
        public List<Book> Books { get; set; }
        public Library(params Book[] books)
        {
            this.Books = books.ToList();
        }

        public IEnumerator<Book> GetEnumerator()
        {
            foreach (var book in Books)
            {
                yield return book;
            }
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return this.GetEnumerator();
        }
    }
}