设计模式：装饰者模式（3）C++版

装饰者模式：动态的将责任附加到对象上。

C++示例代码如下：

/** CONTENTS: DESIGN PATTERN, DECORATOR PATTERN*   AUTHOR: YAO H. WANG*     TIME: 2013-10-19 22:13:19*  EDITION: 1** ALL RIGHTS RESERVED!*/#include <string>#include <iostream>using namespace std;//类class Beverage{public:string description;virtual string getDescription(){return description;}virtual double cost() = 0;};//装饰类class CondimentDecorator: public Beverage{public:Beverage *beverage;virtual string getDescription() = 0;};//具体类class Espresso: public Beverage{public:Espresso(){description = "Espresso";}double cost(){return 1.99;}};class HouseBlend: public Beverage{public:HouseBlend(){description = "HouseBlend";}double cost(){return .89;}};class DarkRoast: public Beverage{public:DarkRoast(){description = "DarkRoast";}double cost(){return .99;}};//具体装饰类class Mocha: public CondimentDecorator{public:Mocha(Beverage *beverage){CondimentDecorator::beverage = beverage;}string getDescription(){return beverage->getDescription() + ", Mocha";}double cost(){return .20 + beverage->cost();}};class Whip: public CondimentDecorator{public:Whip(Beverage *beverage){CondimentDecorator::beverage = beverage;}string getDescription(){return beverage->getDescription() + ", Whip";}double cost(){return .10 + beverage->cost();}};class Soy: public CondimentDecorator{public:Soy(Beverage *beverage){CondimentDecorator::beverage = beverage;}string getDescription(){return beverage->getDescription() + ", Soy";}double cost(){return .15 + beverage->cost();}};//测试void main(){Beverage *beverage = new Espresso();cout << beverage->getDescription() << " $" << beverage->cost() << endl;Beverage *beverage2 = new DarkRoast();beverage2 = new Mocha(beverage2);beverage2 = new Mocha(beverage2);beverage2 = new Whip(beverage2);cout << beverage2->getDescription() << " $" << beverage2->cost() << endl;Beverage *beverage3 = new HouseBlend();beverage3 = new Soy(beverage3);beverage3 = new Mocha(beverage3);beverage3 = new Whip(beverage3);cout << beverage3->getDescription() << " $" << beverage3->cost() << endl;delete beverage;delete beverage2;delete beverage3;}