static void Main(string[] args)
{
GroupTour tour = new GroupTour("International");
tour.AddLocations("Paris");
tour.UpdateTotalCost(100);
Guest g1 = new Guest("Sam");
Guest g2 = new Guest("Mike");
tour.AddObserver(g1);
tour.AddObserver(g2);
tour.AddLocations("Rome");
tour.UpdateTotalCost(100);
tour.RemoveObserver(g1);
tour.AddLocations("Italy");
tour.UpdateTotalCost(300);
Console.Read();
}
//Pull Mechanishm
public void Update(AObservable subject)
{
data = (GroupTour)subject;
Display();
}