static void Main(string[] args)
{
Duck mallard = new MallardDuck();
RubberDuck rubber = new RubberDuck();
Duck rubberDucky = new RubberDuck();
mallard.performFly();
mallard.performQuack();
mallard.swim();
mallard.Display();
rubber.performFly();
rubber.performQuack();
rubber.swim();
rubber.Display();
rubber.setFlyBehaviour(new FlyWithWings());
rubber.performFly();
mallard.setFlyBehaviour(new FlyWithRocket());
mallard.performFly();
mallard.setQuackBehaviour(new StrongQuack());
mallard.performQuack();
rubberDucky.setFlyBehaviour(new FlyWithRocket());
rubberDucky.performQuack();
Console.ReadLine();
}