大话设计模式C++实现--策略模式

最新推荐文章于 2025-10-04 15:25:35 发布

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本文介绍了一种利用策略模式实现的收银系统，该系统能够根据不同优惠策略计算商品总价。通过具体实例展示了正常收费、打折及返现三种策略的具体实现方式，并通过上下文(Context)类来灵活切换策略。

// designpatten2_cashsuper.cpp : 定义控制台应用程序的入口点。
//商城收银软件
//采用策略模式：strategy
//
#include "stdafx.h"
#include<string>
#include<iostream>
using namespace std;

//抽象类作为公共基类
class CashSuper
{
public:
virtual double acceptCash(double money)
{
return -1;
}
};

//正常收费子类，公有继承CashSuper
class CashNormal :public CashSuper
{
public:
double acceptCash(double money) override
{
return money;
}

};

//打折收费子类，公有继承CashSuper
class CashRebate :public CashSuper
{
private:
double moneyRebate = 1;
public:
CashRebate(double moneyRebate)
{
this->moneyRebate = moneyRebate;
}

double acceptCash(double money) override
{
return money*moneyRebate;
}

};

//返现收费子类，公有继承CashSuper
class CashReturn :public CashSuper
{
private:
double moneyCondition=0;
double moneyReturn = 0;
public:
CashReturn(double moneyCondition,double moneyReturn)
{
this->moneyCondition = moneyCondition;
this->moneyReturn = moneyReturn;
}

double acceptCash(double money) override
{
double result = money;
if (money >= moneyCondition)
result = money - ((int)(money / moneyCondition))*moneyReturn;
return result;
}
};

//context类
class CashContext
{
CashSuper* cs;
public:
CashContext(string type)
{
if (type == "正常收费")
cs = new CashNormal();
else if (type == "满300减100")
cs = new CashReturn(300, 100);
else if (type == "打8折")
cs = new CashRebate(0.8);
else
{
std::cerr << "error \n";
exit(1);
}//异常退出程序
}

double GetResult(double money)
{
return cs->acceptCash(money);
}
};

//应该是界面按钮功能，此处用函数代替
double buttun_click(double txtPrice, int txtNum, string type)
{
CashContext csuper = CashContext(type);
double totalPrices = 0;
totalPrices = csuper.GetResult(txtPrice*txtNum);
return totalPrices;
}

int _tmain(int argc, _TCHAR* argv[])
{
double total = 0;
double total1 = 0;

double txtPrice=200;
int txtNum=5;
string type = "打8折";
string type1 = "满300减100";

total = buttun_click(txtPrice, txtNum, type);
total1 = buttun_click(txtPrice, txtNum, type1);

cout << "单价：" << txtPrice << " 数量;" << txtNum << " type:" << type <<" 合计:"<<total<< endl;
cout << "单价：" << txtPrice << " 数量;" << txtNum << " type1:" << type1 << " 合计:" << total1 << endl;
return 0;
}