public static void Main()
{
Duck modelDuck = new ModelDuck();
modelDuck.setFlyBehavior(new FlyWithRocketPower());
modelDuck.display();
modelDuck.performQuack();
modelDuck.performFly();
}
static void Main(string[] args)
{
Duck mallard = new MallardDuck();
mallard.PerformQuack();
mallard.PerformFly();
mallard.Swim();
Duck model = new ModelDuck();
model.Display();
model.PerformQuack();
model.PerformFly();
model.SetFlyBehavior(new FlyRocketPowered());
model.PerformFly();
}