namespace Ch1Duck;

public interface IQuackBehaviour {
    void Quack();
}

public class NormalQuack: IQuackBehaviour {
    public void Quack() {
        Console.WriteLine("Quack");
    }
}

public class MuteQuack : IQuackBehaviour {
    public void Quack() {
        Console.WriteLine("<< Silence >>");
    }
}

public class Squeak: IQuackBehaviour {
    public void Quack() {
        Console.WriteLine("Squeak");
    }
}