static void Main(string[] args)
{
MallardDuck mallardDuck = new MallardDuck();
mallardDuck.Display();
mallardDuck.PerformFly();
mallardDuck.SetFlyingBehavior(new FlyRocketPowered());
mallardDuck.PerformFly();
mallardDuck.PerformQuack();
mallardDuck.Swim();
}