装饰模式【DECORATOR PATTERN 】

decorator.h

/*
 * decorator.h
 *
 *  Created on: Sep 21, 2012
 *      Author: hl
 *  又是虚函数的力量，调用方法和接口不变，只需要改变调用对象！
 */

#ifndef _DECORATOR_H_
#define _DECORATOR_H_
#include <iostream>
using namespace std;

/**
 * @brief 成绩单
 */
class SchoolReport
{
public:
    virtual void reaport() = 0;
    virtual void sign(string name) = 0;
};

/**
 * @brief 第四学期成绩单
 */
class FouthGradeSchoolReport : public SchoolReport
{
public:
    void reaport();
    void sign(string name);
};

/**
 * @brief 装饰器 - 包装下成绩单，增加排名之类的！
 */
class Decorator : public SchoolReport
{
public:
    void reaport()
    {
        fouth.reaport();
        rank();
    }
    void rank()
    {
        cout << "排名 32" << endl;
    }
    void sign(string name)
    {
        fouth.sign(name);
    }
private:
    FouthGradeSchoolReport fouth;
};

#endif /* _DECORATOR_H_ */

decorator.cpp

//============================================================================
// Name        : decorator.cpp
// Author      : hl
// Version     :
// Copyright   : Copyright (c) 2012 Tiros
// Description : decorator pattern in C++, Ansi-style
//============================================================================

#include <iostream>
#include "decorator.h"
using namespace std;

void FouthGradeSchoolReport::reaport()
{
    cout << "语文 45  数学 54" << endl;
}

void FouthGradeSchoolReport::sign(string name)
{
    cout << "家长请签名: " + name << endl;
}

int main()
{
    SchoolReport * pSchoolReport = new Decorator();
    pSchoolReport->reaport();
    /// < 家长一看排名还不错，就签名了！(作者说)
    pSchoolReport->sign("小五");

    return 0;
}