装饰模式，动态地给一个对象添加一些额外的职责。就增加功能来说，Decorator模式相比生成子类更为灵活。

13.1.解释

main()，老爸

ISchoolReport，成绩单接口

CFourthGradeSchoolReport，四年级成绩单

ReportDecorator，成绩单装饰器基类

HighScoreDecorator，最高分装饰器

SortDecorator，班级排名装饰器

说明：对“四年级成绩单”进行装饰，ReportDecorator必然有一个private变量指向ISchoolReport。

注意：

看代码：

// Decorator.cpp//主程序

#include "stdafx.h"

#include "ISchoolReport.h"

#include "FouthGradeSchoolReport.h"

#include "SugarFouthGradeSchoolReport.h"

#include "HighScoreDecorator.h"

#include "SortDecorator.h"

#include <iostream>

using std::cout;

using std::endl;

void DoIt()

{

    ISchoolReport *psr = new CSugarFouthGradeSchoolReport();

    psr->Report();//看成绩单

    psr->Sign("老三");//很开心，就签字了

    delete psr;

}

void DoNew()

{

    cout << "----------分部分进行装饰----------" << endl;

    ISchoolReport *psr = new CFouthGradeSchoolReport();//原装成绩单

    //

    ISchoolReport *pssr = new CSortDecorator(psr);//又加了成绩排名的说明

    ISchoolReport *phsr = new CHighScoreDecorator(pssr);//加了最高分说明的成绩单

    phsr->Report();//看成绩单

    phsr->Sign("老三");//很开心，就签字了

    

    //先装饰哪个不重要，顺序已经在装饰内部确定好，但一定要调用最后一个装饰器的接口。

    //ISchoolReport *phsr = new CHighScoreDecorator(psr);//加了最高分说明的成绩单

    //ISchoolReport *pssr = new CSortDecorator(phsr);//又加了成绩排名的说明

    //pssr->Report();//看成绩单

    //pssr->Sign("老三");//很开心，就签字了

    delete pssr;

    delete phsr;

    delete psr;

}

int _tmain(int argc, _TCHAR* argv[])

{

    //在装饰之前，可以用继承的办法，来进行简单的修饰

    DoIt();

    //但如果需要修饰的项目太多呢？或者装饰的项目不是固定的，继承显然会变得更复杂

    DoNew();

    _CrtSetDbgFlag(_CRTDBG_LEAK_CHECK_DF | _CRTDBG_ALLOC_MEM_DF);

    _CrtDumpMemoryLeaks();

    return 0;

}

//ISchoolReport.h

#pragma once

#include <iostream>

using std::string;

class ISchoolReport

{

public:

    ISchoolReport(void)

    {

    }

    virtual ~ISchoolReport(void)

    {

    }

    virtual void Report() = 0;

    virtual void Sign(string name) = 0;

};

//FouthGradeSchoolReport.h

#pragma once

#include "ischoolreport.h"

class CFouthGradeSchoolReport :

    public ISchoolReport

{

public:

    CFouthGradeSchoolReport(void);

    ~CFouthGradeSchoolReport(void);

    void Report();

    void Sign(string name);

};

//FouthGradeSchoolReport.cpp

#include "StdAfx.h"

#include "FouthGradeSchoolReport.h"

#include <iostream>

using std::cout;

using std::endl;

using std::string;

CFouthGradeSchoolReport::CFouthGradeSchoolReport(void)

{

}

CFouthGradeSchoolReport::~CFouthGradeSchoolReport(void)

{

}

void CFouthGradeSchoolReport::Report()

{

    cout << "尊敬的XXX家长：" << endl;

    cout << "......" << endl;

    cout << "语文62  数学65  体育98  自然63" << endl;

    cout << "......" << endl;

    cout << "                家长签名：" << endl;

}

void CFouthGradeSchoolReport::Sign(string name)

{

    cout << "家长签名为：" << name.c_str() << endl;

}

//ReportDecorator.h

#pragma once

#include "ischoolreport.h"

class CReportDecorator :

    public ISchoolReport

{

public:

    CReportDecorator(ISchoolReport *psr);

    virtual ~CReportDecorator(void);

    void Report();

    void Sign(string name);

private:

    ISchoolReport *m_pSchoolReport;

};

//ReportDecorator.cpp

#include "StdAfx.h"

#include "ReportDecorator.h"

#include <iostream>

using std::string;

CReportDecorator::CReportDecorator(ISchoolReport *psr)

{

    this->m_pSchoolReport = psr;

}

CReportDecorator::~CReportDecorator(void)

{

}

void CReportDecorator::Report()

{

    this->m_pSchoolReport->Report();

}

void CReportDecorator::Sign( string name )

{

    this->m_pSchoolReport->Sign(name);

}

//HighScoreDecorator.h

#pragma once

#include "reportdecorator.h"

#include "ISchoolReport.h"

class CHighScoreDecorator :

    public CReportDecorator

{

public:

    CHighScoreDecorator(ISchoolReport *psr);

    ~CHighScoreDecorator(void);

    void Report();

private:

    void ReportHighScore();

};

//HighScoreDecorator.cpp

#include "StdAfx.h"

#include "HighScoreDecorator.h"

#include <iostream>

using std::cout;

using std::endl;

CHighScoreDecorator::CHighScoreDecorator( ISchoolReport *psr ) : CReportDecorator(psr)

{

}

CHighScoreDecorator::~CHighScoreDecorator(void)

{

}

void CHighScoreDecorator::Report()

{

    this->ReportHighScore();

    this->CReportDecorator::Report();

}

void CHighScoreDecorator::ReportHighScore()

{

    cout << "这次考试语文最高是75， 数学是78， 自然是80" << endl;

}

//SortDecorator.h

#pragma once

#include "reportdecorator.h"

#include "ISchoolReport.h"

class CSortDecorator :

    public CReportDecorator

{

public:

    CSortDecorator(ISchoolReport *psr);

    ~CSortDecorator(void);

    void Report();

private:

    void ReportSort();

};

//SortDecorator.cpp

#include "StdAfx.h"

#include "SortDecorator.h"

#include <iostream>

using std::cout;

using std::endl;

CSortDecorator::CSortDecorator( ISchoolReport *psr ) : CReportDecorator(psr)

{

}

CSortDecorator::~CSortDecorator(void)

{

}

void CSortDecorator::ReportSort()

{

    cout << "我是排名第38名..." << endl;

}

void CSortDecorator::Report()

{

    this->CReportDecorator::Report();

    this->ReportSort();

}

这也是一个比较简单的模式，属于行为型模式。