using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Text;

 using System.Threading.Tasks;

 namespace 简单工厂 {

     class Program {

         static void Main(string[] args) {

             Operation op = Facotry.createFactory("+");

             op.Number1 = ;

             op.Number2 = ;

             int result = op.getResult();

             Console.WriteLine(op.ToString());

             Console.ReadKey();

         }

         class Operation { //父类，封装

             protected int number1;

             protected int number2;

             public int Number1 {

                 get { return number1; }

                 set { number1 = value; }

             }

             public int Number2 {

                 get { return number2; }

                 set { number2 = value; }

             }

             public virtual int getResult() {

                 int result = ;

                 return result;

             }

         }

         class OperationAdd : Operation {

             public override int getResult() {

                 return number1 + number2;

             }

         }

         class OperationSub : Operation {

             public override int getResult() {

                 return number1-number2;

             }

         }

         class Facotry {

             public static Operation createFactory(string ope) {

                 Operation op = null;

                 switch (ope) {

                     case "+":

                         op = new OperationAdd();

                         break;

                     case "-":

                         op = new OperationSub();

                         break;

                 }

                 return op;

             }

         }

     }

 }