策略模式c++版本

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这是大话设计模式中的策略模式的c++版本

//策略模式#include <iostream>using namespace std;enum Cash_type{    NORMALL_CASH = 0,    RETURN_CASH = 1,    DISCOUNT = 2,};//虚基类cashsuperclass CashSuper{public:    //打折函数    double virtual acceptCash(double money)=0;    //虚析构函数    virtual ~CashSuper(){};};//正常收费子类class CashNormal :public CashSuper{public:     double acceptCash(double money) override     {         //正常返回         return money;     }};//打折收费类class CashRebate:public CashSuper{public:    //打折收费    CashRebate(double moneyRebate)    {        _moneyReabate = moneyRebate;    }    double acceptCash(double money) override    {        return money * _moneyReabate;    }private:    double _moneyReabate = 0;};//返利收费,超过设定金额,全部的数值就加入返利计算class CashReturn:public CashSuper{public:    CashReturn(double moneyCondition,double moneyReturn)    {        _moneyCondition = moneyCondition;        _moneyReturn = moneyReturn;    }    double acceptCash(double money) override    {        double result = money;        if(money >= _moneyCondition)        {            result = money - (money/_moneyCondition) * _moneyReturn;        }        return result;    }private://返利条件double _moneyCondition = 0; //返利数值double _moneyReturn = 0;};//定义所有支持的算法的公共接口class CashContext{public:    double GetResult(double money)    {        return _cs->acceptCash(money);    }    //将工厂的对象实例化过程转移至此实现与工厂方法的结合    CashContext(Cash_type type)    {        switch(type)        {            case NORMALL_CASH:                _cs = new CashNormal();                break;            case RETURN_CASH:                _cs = new CashReturn(300,100);                break;            case DISCOUNT:                _cs = new CashRebate(0.8);                break;        }    }private:    CashSuper *_cs;};int main(){    double cash = 500;    //获取收费策略    CashContext *csuper = new CashContext(RETURN_CASH);    //将传入金额    cout<<"在现有优惠策略下消费"<<cash<<",实际支付的金额是:"<<csuper->GetResult(cash)<<endl;    return 0;}

测试输出:
在现有优惠策略下消费500,实际支付的金额是:333.333

策略模式优点:
1.减少了算法类与使用算法类的耦合
2.有助于提取出算法中的公共功能
3.简化单元测试
缺点:
改变的成本比较大
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