//5.工廠模式
//ver1
//回顧簡單工廠模式
class OperationFactory
{
public:static Operation createOperation(char chOper){Operation * op = NULL;switch(chOper){case '+':op = new OperationAdd();break;case '-':op = new OperationSub();break;default:break;}return *op;}
};void main11()
{Operation oper;oper = OperationFactory::createOperation('+');oper.SetNumberA(1.1);oper.SetNumberB(2.2);double result = oper.GetResult();
}//工廠模式:
//工廠接口
class Operation
{
public:Operation(){}~Operation(){}
protected:double _NumberA;double _NumberB;
public:void SetNumberA(double A){_NumberA = A;}double GetNumberA(){return _NumberA;}void SetNumberB(double B){_NumberB = B;}double GetNumberB(){return _NumberB;}virtual double GetResult(){double result = 0;return result;}
};class OperationAdd : public Operation
{
public:virtual double GetResult(){double result = _NumberA + _NumberB;return result;}
};class OperationSub : public Operation
{
public:virtual double GetResult(){double result = _NumberA - _NumberB;return result;}
};class IFactory
{
public:virtual Operation CreateOperation(){Operation * po = NULL;return *po;}
};class AddFactory : public IFactory
{
public:virtual Operation CreateOperation(){Operation * po = new OperationAdd();return *po;}
};class SubFactory : public IFactory
{
public:virtual Operation CreateOperation(){Operation * po = new OperationSub();return *po;}
};void main1()
{IFactory * pif = new AddFactory();Operation po = pif->CreateOperation();po.SetNumberA(1.1);po.SetNumberB(2.2);double result = po.GetResult();
}
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//簡單工廠模式的最大優點在于工廠類中包含了必要的邏輯判斷，根據客戶端的選擇條件動態實例化相關的類，
//對于客戶端來說，去除了與具體產品的依賴。
//工廠模式，定義一個用于創建對象的接口，讓子類決定實例化哪一個類。工廠方法使一個類的實例化延遲到其子類。
//工廠模式實現時，客戶端需要決定實例化哪一個工廠來實現運算類，選擇判斷的問題還是存在，也就是說，工廠方式把
//簡單工廠的內部邏輯判斷移到了客戶端代碼來進行。你想要加功能，本來是改工廠類，現在是改客戶端。
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//5.工廠模式
//ver2
class LeiFeng
{
public:void Sweep(){//打掃}void Wash(){//洗衣}
};//學習雷鋒大學生
class Undergraduate : public LeiFeng
{};//志愿者
class Volunteer : public LeiFeng
{};//簡單雷鋒工廠
class SimpleFactory
{
public:static LeiFeng CreateLeiFeng(char cType){LeiFeng * plf = NULL;switch (cType){case '1': //大學生plf = new Undergraduate();break;case '2': //志愿者plf = new Volunteer();break;default:break;}return *plf;}
};void main21()
{LeiFeng stuA = SimpleFactory::CreateLeiFeng('1');stuA.Sweep();LeiFeng volA = SimpleFactory::CreateLeiFeng('2');volA.Wash();
}//雷鋒工廠
class IFactory
{
public://IFactory(){}LeiFeng CreateLeiFeng(){LeiFeng * plf = new LeiFeng();return *plf;}
};//大學生工廠
class UndergraduateFactory : public IFactory
{
public://UndergraduateFactory(){}LeiFeng CreateLeiFeng(){LeiFeng *plf = new Undergraduate();return *plf;}
};//志愿者工廠
class VolunteerFactory : public IFactory
{
public://VolunteerFactory(){}LeiFeng CreateLeiFeng(){LeiFeng * plf = new Volunteer();return *plf;}
};void main22()
{IFactory * pf = new UndergraduateFactory();LeiFeng stu = pf->CreateLeiFeng();stu.Sweep();stu.Wash();
}
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//工廠模式客服了簡單工廠違背開放-封閉原則的缺點，又保持了封裝對象創建過程的優點。
//缺點:每加一個產品，就需要加一個產品工廠的類，增加了額外的開發量。
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