Design Patterns 1 of 3 - Creational Design Patterns

using System;

namespace AbstractFactory
{
    static class Program
    {

        static void Main()
        {
            AbstractFactory factory1 = new ConcreteFactory1();
            var client1 = new Client(factory1);
            client1.Run();

            AbstractFactory factory2 = new ConcreteFactory2();
            var client2 = new Client(factory2);
            client2.Run();
        }
    }

    class Client
    {
        private readonly AbstractProductA _abstractProductA;
        private readonly AbstractProductB _abstractProductB;

        public Client(AbstractFactory factory)
        {
            _abstractProductB = factory.CreateProductB();
            _abstractProductA = factory.CreateProductA();
        }

        public void Run()
        {
            _abstractProductB.Interact(_abstractProductA);
        }
    }


    abstract class AbstractProductA
    {
    }

    abstract class AbstractProductB
    {
        public abstract void Interact(AbstractProductA a);
    }

    class ProductA1 : AbstractProductA
    {
    }

    class ProductB1 : AbstractProductB
    {
        public override void Interact(AbstractProductA a)
        {
            Console.WriteLine(GetType().Name +
              " interacts with " + a.GetType().Name);
        }
    }

    class ProductA2 : AbstractProductA
    {
    }

    class ProductB2 : AbstractProductB
    {
        public override void Interact(AbstractProductA a)
        {
            Console.WriteLine(GetType().Name +
              " interacts with " + a.GetType().Name);
        }
    }

    abstract class AbstractFactory
    {
        public abstract AbstractProductA CreateProductA();
        public abstract AbstractProductB CreateProductB();
    }

    class ConcreteFactory1 : AbstractFactory
    {
        public override AbstractProductA CreateProductA()
        {
            return new ProductA1();
        }
        public override AbstractProductB CreateProductB()
        {
            return new ProductB1();
        }
    }

    class ConcreteFactory2 : AbstractFactory
    {
        public override AbstractProductA CreateProductA()
        {
            return new ProductA2();
        }
        public override AbstractProductB CreateProductB()
        {
            return new ProductB2();
        }
    }
}