Program.cs

namespace Ducks
{
 internal class Duck
 {
 private IQuackBehaviour _quacker;
 private IFlyBehaviour _flyer;


 public IQuackBehaviour Quacker {
 set
 {
 _quacker = value;
 }
 }

 public IFlyBehaviour Flyer
 {
 set
 {
 _flyer = value;
 }
 }


 protected void PerformQuack()
 {
 _quacker.Quack();
 }

 protected void PerformFly()
 {
 _flyer.Fly();
 }
 }

 internal class MallardDuck : Duck
 {
 public MallardDuck()
 {
 Flyer = new FlyNope();
 Quacker = new QuackNope();
 }

 public void Display()
 {
 PerformFly();
 PerformQuack();
 }
 }

 internal static class Program
 {
 private static void Main()
 {
 var mallard = new MallardDuck {Quacker = new QuackNormal()};
 mallard.Display();
 mallard.Flyer = new FlyWings();
 mallard.Display();

 }
 }
}