public Library()
{
IComparer <Book> comparer = new BookComparer();
books = new SortedSet <Book>(comparer);
}
public Library()
{
BookComparer comparer = new BookComparer();
books = new SortedList(comparer);
}
public Library(IEnumerable <Book> books)
{
IComparer <Book> comparer = new BookComparer();
this.books = new SortedSet <Book>(books, comparer);
}