8、工厂方法模式.cs

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

namespace ConsoleApplication1
{
    /// <summary>
    /// 工厂模式存在类与switch语句的高耦合，增加新的类 需要去增加case分支，违背了开放-封闭原则
    /// 工厂方法模式可以解决这个问题。
    /// </summary>
    class 工厂方法模式
    {
        public void Main()
        {
            SubFactory sf=new SubFactory();
            Operator op=sf.CreateOperator();
            op.NumberA = 10;
            op.NumberB = 5;
            op.GetResult();
        }
    }
    public abstract  class Operator
    {
        public double NumberA;
        public double NumberB;
        public virtual double GetResult()
        {
            return 0;
        }
    }
    public class Add1:Operator
    {
        public override double GetResult()
        {
            return NumberA+NumberB;
        }
    }
    public class Sub1:Operator
    {
        public override double GetResult()
        {
            return NumberA-NumberB;
        }
    }

    interface IFactory
    {
        Operator CreateOperator();
    }
    class AddFactory:IFactory
    {
        public  Operator CreateOperator()
        {
            return new Add1();
        }
    }
    class SubFactory:IFactory
    {
         public Operator CreateOperator()
         {
             return  new Sub1();
         }
    }
}