using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        ICollection<IDuck> flock = new List<IDuck>();

        IDuck ninjaDuck = new Duck(new SilentQuacking(), new StealthFlying());

        IDuck noisyDuck = new Duck(new LoudQuacking(), new LoudFlying());

        Goat goat = new Goat();

        GoatToDuckAdapter adapter = new GoatToDuckAdapter(goat);

        flock.Add(ninjaDuck);

        flock.Add(noisyDuck);

        flock.Add(adapter);

        IDuck duckFlock = new DuckFlock(flock);

        IObserver flyingDuckObserver = new FlyingDuckObserver();

        DuckSimulator sim = new DuckSimulator(duckFlock);

        sim.Subscribe(flyingDuckObserver);

        sim.MakeDuckFly();

        sim.MakeDuckQuack();

    }

}

​

public class DuckSimulator : IObservable {

    private IDuck duck;

    private ICollection<IObserver> observers;

    public DuckSimulator(IDuck duck){

        this.duck = duck;

        this.observers = new List<IObserver>();

    }

    public void MakeDuckFly(){

        duck.Fly();

        foreach(var o in observers){

            o.Notify();

        }

    }

    public void MakeDuckQuack(){

        duck.Quack();

    }

    public void Subscribe(IObserver obs){

        observers.Add(obs);

    }

    public void Unsubscribe(IObserver obs){

        observers.Remove(obs);

    }

}

​

public class FlyingDuckObserver : IObserver {

    public void Notify(){

        Console.WriteLine("*sees a duck flying");

    }

}

​

public class QuackingDuckObserver : IObserver {

    public void Notify(){

        Console.WriteLine("*hears a duck quacking");

    }

}

​

public class Duck : IDuck {

        private IQuackBehavior quack;

        private IFlyBehavior fly;

        public Duck(IQuackBehavior q, IFlyBehavior f){

            this.quack = q;

            this.fly = f;

        }

        public void Quack(){

            quack.Quack();

        }

        public void Fly(){

            fly.Fly();

        }

}

​

public class DuckFlock : IDuck {

    private ICollection<IDuck> ducks;

    public DuckFlock(ICollection<IDuck> ducks){

        this.ducks = ducks; 

    }

    public void Fly(){

        foreach(var duck in ducks){

            duck.Fly();

        }

    }

    public void Quack(){

        foreach(var duck in ducks){

            duck.Quack();

        }

    }

}

​

public interface IQuackBehavior {

    void Quack();

}

​

public class LoudQuacking : IQuackBehavior {

    public void Quack(){

        Console.WriteLine("*Louud Quacking noises");    

    }

}

​

public class SilentQuacking : IQuackBehavior {

    public void Quack(){

        Console.WriteLine("*Silent Quacking noises");   

    }

}

​

public interface IFlyBehavior {

    void Fly(); 

}

​

public class StealthFlying : IFlyBehavior {

    public void Fly(){

        Console.WriteLine("*Silently flying");  

    }

}

​

public class LoudFlying : IFlyBehavior {

    public void Fly(){

        Console.WriteLine("*Noisily flying");   

    }

}

​

public interface IDuck : IQuackBehavior, IFlyBehavior {

}

​

public class Goat {

    public Goat(){

    }

    public void MakeGoatSound(){

        Console.WriteLine("Meeeh-ee-ee-ee");

    }

}

​

public class GoatToDuckAdapter : IDuck {

    private Goat goat;

    public GoatToDuckAdapter(Goat goat){

        this.goat = goat;

    }

    public void Fly(){

        Console.WriteLine("*Jumping while ears flapping noises");

    }

    public void Quack(){

        goat.MakeGoatSound();

    }

}

​

public interface IObservable {

    void Subscribe(IObserver obs);

    void Unsubscribe(IObserver obs);

}

​

public interface IObserver {

    void Notify();

}

​

​

​