简单工厂模式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace 简单工厂模式
{
   public class OperationFactory
   {
       public static Operation craateOperation(string operate)
       {
           Operation oper = null;
           switch (operate)
           {
               case "+":
                   oper = new OpertionAdd();
                   break;
               case "-":
                   oper = new OpertionSub();
                   break;
               case "*":
                   oper = new OpertionMul();
                   break;
               case "/":
                   oper = new OpertionDiv();
                   break;   
           }
           return oper;
       }
   }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace 简单工厂模式
{
   public class Operation
   {
       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;
       }
   }
}