public static void Run() { Subject RedMI = new Subject("Red MI Mobile", 10000, "Out Of Stock"); Observer user1 = new Observer("John", RedMI); Observer user2 = new Observer("Doe", RedMI); Observer user3 = new Observer("Joanna", RedMI); Console.WriteLine("Red MI Mobile current state : " + RedMI.GetAvailability()); Console.WriteLine(); RedMI.SetAvailability("Available"); Console.Read(); }