Design Pattern——Factory_DP

namespace TEST
{
    //用于生成一个对应的操作类，这个工厂只是用来产生操作类的，不做其他只用
    public  class Factory
    {
        public Operate GetOpetration(string mark)
        {
            switch(mark)
            {
                case "+":
                    return new OperateAdd();
                    break;
                case "-":
                    return new OperateSub();
                    break;
                case "*":
                    return new OperateMultiply();
                    break;
                case "/":
                    return new OperateDivision();
                    break;
                default:
                    return null;
                    break;
            }
        }
    }
    //这个类是用来执行相关的操作的
    public abstract class Operate
    {
       public double operateTwo { get; set; }
       public double operateOne { get; set; }
       public  abstract string Opetration();
    }
    public class OperateAdd:Operate
    {
        public override string Opetration()
        {
            return Convert.ToString(base.operateOne + base.operateTwo);
        }
    }
    public class OperateSub : Operate
    {
        public override string Opetration()
        {
            return Convert.ToString(this.operateOne - this.operateTwo);
        }
    }
    public class OperateMultiply : Operate
    {
        public override string Opetration()
        {
            return Convert.ToString(this.operateOne*this.operateTwo);
        }
    }
    public class OperateDivision : Operate
    {
        public override string Opetration()
        {
            if (this.operateTwo != )
                return Convert.ToString(this.operateOne / this.operateTwo);
            else
                return "input error";
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                double num1=Convert.ToDouble( Console.ReadLine());
                double num2 =Convert.ToDouble( Console.ReadLine());
                string op =  Convert.ToString(Console.ReadLine());
                var factory = new Factory();
                var Opetration = factory.GetOpetration(op);
                Opetration.operateOne = num1;
                Opetration.operateTwo = num2;
                Console.WriteLine(Opetration.Opetration());

                Console.Read(); Console.Read();
            }
            catch (Exception ex)
            {
                Console.WriteLine("程序出错");
            }

        }
    }
}