static void Main(string[] args) { Subject subject = new Subject(5); // Observer1 takes a subscription to the store var observer1 = new Observar("Observer 1"); subject.Subscribe(observer1); // Observer2 also subscribes to the store subject.Subscribe(new Observar("Observer 2")); subject.Data++; // Observer1 unsubscribes and Observer3 subscribes to notifications. subject.Unsubscribe(observer1); subject.Subscribe(new Observar("Observer 3")); subject.Data++; Console.ReadLine(); }