装饰者模式：动态地将责任附加到对象上。想要扩展功能，装饰者提供有别于继承的另一种选择。——《HEAD FIRST 设计模式》

   我的c++代码：

#ifndef DESIGN_DECORATOR_H_#define DESIGN_DECORATOR_H_#include 
     
      class Beverage{public:    virtual ~Beverage(){}public:   virtual std::string getDescription();   virtual int cost();protected:   std::string m_descri;};class CondimentDecorator:public Beverage{public:    virtual ~CondimentDecorator(){}};////class HouseBlend:public Beverage{public:    HouseBlend();    virtual ~HouseBlend(){}public:    virtual std::string getDescription();    virtual int cost();};class DarkRoast:public Beverage{public:    DarkRoast();    virtual  ~DarkRoast(){}public:    virtual std::string getDescription();    virtual int cost();};class Espresso:public Beverage{public:    Espresso();    virtual ~Espresso(){}public:    virtual std::string getDescription();    virtual int cost();};class Decaf:public Beverage{public:    Decaf();    virtual ~Decaf(){}public:    virtual std::string getDescription();    virtual int cost();};////class Milk:public CondimentDecorator{public:    Milk(Beverage* b);    virtual ~Milk(){}public:    virtual std::string getDescription();    virtual int cost();private:    Beverage* m_b;};class Mocha:public CondimentDecorator{public:    Mocha(Beverage* b);    virtual ~Mocha(){}public:    virtual std::string getDescription();    virtual int cost();private:    Beverage* m_b;};class Soy:public CondimentDecorator{ public:    Soy(Beverage* b);    virtual ~Soy(){} public:    virtual std::string getDescription();    virtual int cost(); private:    Beverage* m_b;};class Whip:public CondimentDecorator{public:    Whip(Beverage* b);    virtual ~Whip(){}public:    virtual std::string getDescription();    virtual int cost();private:    Beverage* m_b;};#endif // DESIGN_DECORATOR_H_
     

#include "decorator.h"std::string Beverage::getDescription(){    return this->m_descri;}int Beverage::cost(){    return 0;}HouseBlend::HouseBlend(){    this->m_descri = "HouseBlend";}std::string HouseBlend::getDescription(){    return Beverage::getDescription();}int HouseBlend::cost(){    return 1;}DarkRoast::DarkRoast(){    this->m_descri = "DarkRoast";}std::string DarkRoast::getDescription(){    return Beverage::getDescription();}int DarkRoast::cost(){    return 2;}Espresso::Espresso(){    this->m_descri = "Espresso";}std::string Espresso::getDescription(){    return Beverage::getDescription();}int Espresso::cost(){    return 3;}Decaf::Decaf(){    this->m_descri = "Decaf";}std::string Decaf::getDescription(){    return Beverage::getDescription();}int Decaf::cost(){    return 4;}Milk::Milk(Beverage* b){    this->m_b = b;}std::string Milk::getDescription(){    return this->m_b->getDescription() + ",Milk";}int Milk::cost(){    return this->m_b->cost() + 1;}Mocha::Mocha(Beverage* b){    this->m_b = b;}std::string Mocha::getDescription(){    return this->m_b->getDescription() + ",Mocha";}int Mocha::cost(){    return this->m_b->cost() + 2;}Soy::Soy(Beverage* b){    this->m_b = b;}std::string Soy::getDescription(){    return this->m_b->getDescription() + ",Soy";}int Soy::cost(){    return this->m_b->cost() + 3;}Whip::Whip(Beverage* b){    this->m_b = b;}std::string Whip::getDescription(){    return this->m_b->getDescription() + ",Whip";}int Whip::cost(){    return this->m_b->cost() + 4;}

         

个人感悟：待留。