static void Main(string[] args)
{
Teller teller = new Teller();
Hero hero = new Hero();
teller.SetCommand(new AttackCommand(hero));
teller.Attack();
Console.WriteLine();
Character character = new Character();
character.Attack();
character.Hide();
character.Rest();
Console.WriteLine();
Person J = new Person();
J.SetName("John");
J.SetWeapon("Gun");
Console.WriteLine($"{J.name}:{J.weapon}");
Memento memento = J.GetState();
J.SetName("Mike");
J.SetWeapon("Sword");
Console.WriteLine($"{J.name}:{J.weapon}");
J.SetState(memento);
Console.WriteLine($"{J.name}:{J.weapon}");
Console.WriteLine();
Observable observable = new Observable();
ConcreteObserverA observerA = new ConcreteObserverA();
observable.RegisterObserver(observerA);
ConcreteObserverB observerB = new ConcreteObserverB();
observable.RegisterObserver(observerB);
observable.DoSomeWork();
observable.DoSomeWork();
observable.RemoveObserver(observerA);
observable.DoSomeWork();
Console.ReadKey();
}