using System;

public class Program

{

    public static void Main()

    {

      // Create and run the African animal world

      ContinentFactory africa = new AfricaFactory();

      AnimalWorld world = new AnimalWorld(africa);

      world.RunFoodChain();

      // Create and run the American animal world

     // ContinentFactory america = new AmericaFactory();

     // world = new AnimalWorld(america);

     // world.RunFoodChain();

      // Wait for user input

      Console.ReadLine();

}

}   

    public  class Wildebeest : Herbivore

  {

  }

  /// <summary>

  /// The 'ProductB1' class

  /// </summary>

public  class Lion : Carnivore

  {

    public override void Eat(Herbivore h)

    {

      // Eat Wildebeest

      Console.WriteLine(this.GetType().Name +

        " eats " + h.GetType().Name);

    }

  }

​

​

public  class AnimalWorld

  {

    private Herbivore _herbivore;

    private Carnivore _carnivore;

    // Constructor

    public AnimalWorld(ContinentFactory factory)

    {

      _carnivore = factory.CreateCarnivore();

      _herbivore = factory.CreateHerbivore();

    }

    public void RunFoodChain()

    {

      _carnivore.Eat(_herbivore);

    }

  }

​

​

​

public  class AfricaFactory : ContinentFactory

  {

    public override Herbivore CreateHerbivore()

    {

      return new Wildebeest();

    }

    public override Carnivore CreateCarnivore()

    {

      return new Lion();

    }

  }

​

​

​

public  abstract class Herbivore

  {

  }

public  abstract class Carnivore

  {

    public abstract void Eat(Herbivore h);

  }

​

​

public abstract class ContinentFactory

  {

    public abstract Herbivore CreateHerbivore();

    public abstract Carnivore CreateCarnivore();

  }