static void Main(string[] args)
{
CoffieTableBook ctBook = new CoffieTableBook();
ctBook.Author = "Stephen King";
ctBook.ISBN = 123456;
ctBook.Title = "The Shining";
ctBook.Price = 150.0;
ctBook.Price = 40.0;
Book book = new Book();
book.Author = "J.R.R. Tolkien";
book.ISBN = 456789;
book.Title = "The Lord of the Rings, The return of the King";
book.Price = 25.0;
TextBook tBook = new TextBook();
tBook.Author = "Tim Dams";
tBook.ISBN = 123789;
tBook.Title = "Zie Scherper";
tBook.Price = 0.0;
tBook.Price = 20.0;
Console.WriteLine(ctBook);
Console.WriteLine(tBook);
Console.WriteLine(book);
Console.WriteLine();
Console.WriteLine(ctBook.Equals(book));
book.ISBN = ctBook.ISBN;
Console.WriteLine(ctBook.Equals(book));
Console.WriteLine(book.Equals(ctBook));
Book b = Book.Add(book, ctBook);
Console.WriteLine(b);
}
