策略模式

最新推荐文章于 2025-02-08 16:16:45 发布

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#策略模式设计模式

本文介绍了一种使用设计模式实现折扣策略的方法。通过定义抽象基类CashSuper及其派生类CashNormal、CashRebate和CashReturn来模拟不同类型的折扣计算方式。CashContext类则负责根据类型选择具体的折扣策略并应用到实际的金额计算中。

#include <iostream>

using namespace std;

class CashSuper
{
    public:
        virtual double acceptCash(double money) = 0;
};

class CashNormal: public CashSuper
{
    public:
        double acceptCash(double money)
        {
            return money;
        }
};

class CashRebate: public CashSuper
{
    public:
        CashRebate(double moneyRebate):m_moneyRebate(moneyRebate){}
        double acceptCash(double money)
        {
            return money * m_moneyRebate;
        }

    private:
        double m_moneyRebate;
};

class CashReturn: public CashSuper
{
    public:
        CashReturn(double moneyCondition, double moneyReturn):m_moneyCondition(moneyCondition), m_moneyReturn(moneyReturn){}
        double acceptCash(double money)
        {
            double result = money;
            if (money >= m_moneyCondition)
            {
                result = money - (int)(money / m_moneyCondition) * m_moneyReturn;
            }

            return result;
        }
    
    private:
        double m_moneyCondition;
        double m_moneyReturn;
};

class CashContext
{
    public:
        CashContext(int type):m_cs(NULL)
        {
            switch (type)
            {
                case 1:
                    m_cs = new CashNormal;
                    break;
                case 2:
                    m_cs = new CashReturn(300, 100);
                    break;
                case 3:
                    m_cs = new CashRebate(0.8);
                    break;
            }
        }

    double GetResult(double money)
    {
        double result = -1;
        if (m_cs)
            result = m_cs->acceptCash(money);

        return result;
    }

    private:
        CashSuper * m_cs;
};

int main()
{
    CashContext cc1(1);
    cout << cc1.GetResult(389) << endl;

    CashContext cc2(2);
    cout << cc2.GetResult(602) << endl;

    CashContext cc3(3);
    cout << cc3.GetResult(389) << endl;

    return 0;
}