裝飾模式，動態地給一個對象添加一些額外的職責。就增加功能來說，Decorator模式相比生成子類更為靈活。

13.1.解釋

main()，老爸

ISchoolReport，成績單接口

CFourthGradeSchoolReport，四年級成績單

ReportDecorator，成績單裝飾器基類

HighScoreDecorator，最高分裝飾器

SortDecorator，班級排名裝飾器

說明：對“四年級成績單”進行裝飾，ReportDecorator必然有一個private變量指向ISchoolReport。

注意：

看代碼：

// 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();//看成績單
??? psr->Sign("老三");//很開心，就簽字了
??? delete psr;
}
void DoNew()
{
??? cout << "----------分部分進行裝飾----------" << endl;
??? ISchoolReport *psr = new CFouthGradeSchoolReport();//原裝成績單
??? //
??? ISchoolReport *pssr = new CSortDecorator(psr);//又加了成績排名的說明
??? ISchoolReport *phsr = new CHighScoreDecorator(pssr);//加了最高分說明的成績單
??? phsr->Report();//看成績單
??? phsr->Sign("老三");//很開心，就簽字了
???
??? //先裝飾哪個不重要，順序已經在裝飾內部確定好，但一定要調用最后一個裝飾器的接口。
??? //ISchoolReport *phsr = new CHighScoreDecorator(psr);//加了最高分說明的成績單
??? //ISchoolReport *pssr = new CSortDecorator(phsr);//又加了成績排名的說明
??? //pssr->Report();//看成績單
??? //pssr->Sign("老三");//很開心，就簽字了

??? delete pssr;
??? delete phsr;
??? delete psr;
}
int _tmain(int argc, _TCHAR* argv[])
{
??? //在裝飾之前，可以用繼承的辦法，來進行簡單的修飾
??? DoIt();

??? //但如果需要修飾的項目太多呢？或者裝飾的項目不是固定的，繼承顯然會變得更復雜
??? 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家長：" << endl;
??? cout << "......" << endl;
??? cout << "語文62? 數學65? 體育98? 自然63" << endl;
??? cout << "......" << endl;
??? cout << "??????????????? 家長簽名：" << endl;
}
void CFouthGradeSchoolReport::Sign(string name)
{
??? cout << "家長簽名為：" << 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 << "這次考試語文最高是75， 數學是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();
}

這也是一個比較簡單的模式，屬于行為型模式。

轉載于:https://www.cnblogs.com/wanggary/archive/2011/04/18/2020254.html

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