static void Main(string[] args)
{
Hotel hotel = new Hotel();
hotel.bookRum();
RoomKeyCard rk = new RoomKeyCard();
rk.useKeyCard(hotel);//association relation to hotell
}
static void Main(string[] args)
{
Hotel hotel = new Hotel();
hotel.hotelName = "Grand";
Console.WriteLine($"Welcome to: {hotel.hotelName}");
hotel.bookRoom();
RoomKeyCard rk = new RoomKeyCard();
rk.useKeyCard();
Console.ReadLine();
}