Factory, Abstract Factory and Factory Method

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Simple Sample.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GossipDesignPattern.SimpleFactory
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("input first number:");
            string A = Console.ReadLine();

            Console.Write("(+,-,*,/): ");
            string B = Console.ReadLine();

            Console.WriteLine("input second number:");

            string C = Console.ReadLine();

            string D = "";

            if (B == "+")
                D = Convert.ToString(Convert.ToDouble(A) + Convert.ToDouble(C));
            if (B == "-")
                D = Convert.ToString(Convert.ToDouble(A) - Convert.ToDouble(C));
            if (B == "*")
                D = Convert.ToString(Convert.ToDouble(A) * Convert.ToDouble(C));
            if (B == "/")
                D = Convert.ToString(Convert.ToDouble(A) / Convert.ToDouble(C));

            Console.WriteLine("result: " + D);
        }
    }

    class ProgramV2
    {
        static void Main(string[] args)
        {
            try
            {
                Console.Write("input first number:");
                string strNumberA = Console.ReadLine();

                Console.Write("(+,-,*,/): ");
                string strOperate = Console.ReadLine();

                Console.WriteLine("input second number:");
                string strNumberB = Console.ReadLine();

                string strResult = "";

                switch (strOperate)
                { 
                    case "+":
                        strResult = Convert.ToString(Convert.ToDouble(strNumberA) + Convert.ToDouble(strNumberB));
                        break;
                    case "-":
                        strResult = Convert.ToString(Convert.ToDouble(strNumberA) - Convert.ToDouble(strNumberB));
                        break;
                    case "*":
                        strResult = Convert.ToString(Convert.ToDouble(strNumberA) * Convert.ToDouble(strNumberB));
                        break;
                    case "/":
                        if (strNumberB != "0")
                            strResult = Convert.ToString(Convert.ToDouble(strNumberA) / Convert.ToDouble(strNumberB));
                        else
                            strResult = "Divisor can't be 0";
                        break;
                }
                Console.WriteLine("result: " + strResult);

                Console.ReadLine();
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error input:" + ex.ToString());
            }
        }
    }

    public class Operation
    {
        public static double GetResult(double numberA, double numberB, string operate)
        {
            double result = 0d;
            switch (operate)
            {
                case "+":
                    result = numberA + numberB;
                    break;
                case "-":
                    result = numberA - numberB;
                    break;
                case "*":
                    result = numberA * numberB;
                    break;
                case "/":
                    result = numberA / numberB;
                    break;
            }

            return result;
        }

        static void Main(string[] args)
        {
            try
            {
                Console.Write("input first number:");
                string strNumberA = Console.ReadLine();

                Console.Write("(+,-,*,/): ");
                string strOperate = Console.ReadLine();

                Console.WriteLine("input second number:");
                string strNumberB = Console.ReadLine();

                string strResult = "";
                
                strResult = Convert.ToString(Operation.GetResult(Convert.ToDouble(strNumberA), Convert.ToDouble(strNumberB), strOperate));

                Console.WriteLine("result: " + strResult);

                Console.ReadLine();
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error input:" + ex.ToString());
            }
        }
    }

    public class OperationBase
    {
        private double _numberA = 0;
        private double _numberB = 0;

        public double NumberA {
            get { return _numberA; }
            set { _numberA = value; }
        }

        public double NumberB
        {
            get { return _numberB; }
            set { _numberB = value; }
        }

        public virtual double GetResult()
        {
            double result = 0;
            return result;
        }
    }

    class OperationAdd : OperationBase
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA + NumberB;
            return result;
        }
    }

    class OperationSub : OperationBase
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA - NumberB;
            return result;
        }
    }

    class OperationMul : OperationBase
    {
        public override double GetResult()
        {
            double result = 0;
            result = NumberA * NumberB;
            return result;
        }
    }

    class OperationDiv : OperationBase
    {
        public override double GetResult()
        {
            double result = 0;
            if (NumberB == 0)
                throw new Exception("Divisor can't be 0");
            
            result = NumberA / NumberB;
            
            return result;
        }
    }

    public class OperationFactory
    {
        public static OperationBase CreateOperate(string operate)
        {
            OperationBase oper = null;
            switch (operate)
            {
                case "+":
                    oper = new OperationAdd();
                    break;
                case "-":
                    oper = new OperationSub();
                    break;
                case "*":
                    oper = new OperationMul();
                    break;
                case "/":
                    oper = new OperationDiv();
                    break;
            }

            return oper;
        }

        static void main(string[] args)
        {
            OperationBase oper;
            oper = OperationFactory.CreateOperate("+");
            oper.NumberA = 1;
            oper.NumberB = 2;
            double result = oper.GetResult();
        }
    }

    public class FactoryMethod
    {
        
        interface IFactory
        {
            OperationBase CreateOperation();
        }

        class AddFactory : IFactory
        {
            public OperationBase CreateOperation()
            {
                return new OperationAdd();
            }
        }

        class SubFactory : IFactory
        {
            public OperationBase CreateOperation()
            {
                return new OperationSub();
            }
        }

        class MulFactory : IFactory
        {
            public OperationBase CreateOperation()
            {
                return new OperationMul();
            }
        }

        class DivFactory : IFactory
        {
            public OperationBase CreateOperation()
            {
                return new OperationDiv();
            }
        }

        static void main(string[] args)
        {
            IFactory operFactory = new AddFactory();
            OperationBase oper = operFactory.CreateOperation();
            oper.NumberA = 1;
            oper.NumberB = 2;
            double result = oper.GetResult();
        }
    }
}

LeiFeng.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GossipDesignPattern.SimpleFactory
{
    // 简单工厂模式的最大优点在于工厂类中包含了必要的逻辑判断, 根据客户端的选择条件动态实例化相关的类，对于客户端来说，去除了与具体产品的依赖。
    class LeiFeng
    {
        public void Sweep()
        {
            Console.WriteLine("Sweep!");
        }

        public void Wash()
        {
            Console.WriteLine("Wash!");
        }

        public void BuyRice()
        {
            Console.WriteLine("Buy Rice!");
        }
    }

    class Undergraduate: LeiFeng
    { 
        public void IamUndergraduate()
        {
            Console.WriteLine("I am undergraduate!");
        }
    }

    class ProgramV3
    {
        static void main(string [] args)
        {
            LeiFeng xueleifeng = new Undergraduate();

            xueleifeng.BuyRice();
            xueleifeng.Sweep();
            xueleifeng.Wash();

            LeiFeng student1 = new Undergraduate();
            student1.BuyRice();

            LeiFeng student2 = new Undergraduate();
            student1.Sweep();

            LeiFeng student3 = new Undergraduate();
            student1.Wash();
        }
    }

    class Volunteer : LeiFeng
    {
    }

    class SimpleFactory
    {
        public static LeiFeng CreateLeiFeng(string type)
        {
            LeiFeng result = null;
            switch (type)
            {
                case "Undergraduate":
                    result = new Undergraduate();
                    break;
                case "Volunteer":
                    result = new Volunteer();
                    break;
            }

            return result;
        }

        static void main(string[] args)
        {
            LeiFeng studentA = SimpleFactory.CreateLeiFeng("Undergraduate");

            studentA.BuyRice();

            LeiFeng studentB = SimpleFactory.CreateLeiFeng("Undergraduate");

            studentB.Sweep();

            LeiFeng studentC = SimpleFactory.CreateLeiFeng("Undergraduate");

            studentC.Wash();
        }
    }

    //工厂方法克服了简单工厂违背开放-封闭原则的缺点，又保持了封装对象创建过程的优点
    class FactoryMethodForLeiFeng
    {
        interface ILeiFengFactory
        {
            LeiFeng CreateLeiFeng();
        }

        class UndergraduateFactory : ILeiFengFactory
        {
            public LeiFeng CreateLeiFeng()
            {
                return new Undergraduate();
            }
        }

        class VolunteerFactory : ILeiFengFactory
        {
            public LeiFeng CreateLeiFeng()
            {
                return new Volunteer();
            }
        }

        static void main(string[] args)
        {
            ILeiFengFactory factory = new UndergraduateFactory();

            LeiFeng student = factory.CreateLeiFeng();

            student.BuyRice();
            student.Sweep();
            student.Wash();
        }
    }
}