中介者模式之C++实现

814247614

　　可以把邮箱想象成师生交流的一个中介者，它需要知道老师和学生的邮箱地址。
　　学生和老师都需要维护一个邮箱对象，利用它向彼此发消息。

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

class Mail;
class User;
class Mail
{
public:
    virtual void SendMail(string message, User *user) {};
};
class User
{
protected:
    Mail *mail;
public:
    User(Mail *email)
    {
        mail = email;
    }
};
class Student: public User
{
public:
    Student(Mail *email) : User(email){}
    void SendMail(string message)
    {
        mail->SendMail(message, this);
    }
    void ReceiveMail(string message)
    {
        cout << "学生收到邮件：" << message << endl;
    }
};
class Professor: public User
{
public:
    Professor(Mail *email) : User(email){}
    void SendMail(string message)
    {
        mail->SendMail(message, this);
    }
    void ReceiveMail(string message)
    {
        cout << "教授收到邮件：" << message << endl;
    }
};
class SchoolMail : public Mail
{
private:
    Student *student;
    Professor *professor;
public:
    void SetStudent(Student *stu)
    {
        student = stu;
    }
    void SetProfessor(Professor *teacher)
    {
        professor = teacher;
    }
    void SendMail(string message, User *user)
    {
        if (user == professor)
        {
            student->ReceiveMail(message);
        }
        else if (user == student)
        {
            professor->ReceiveMail(message);
        }
    }
};
int main(void)
{
    SchoolMail *mail = new SchoolMail;
    Student *student = new Student(mail);
    Professor *professor = new Professor(mail);
    mail->SetProfessor(professor);
    mail->SetStudent(student);
    professor->SendMail("请以XX为题写一篇论文");
    student->SendMail("好的，我现在开始准备论文材料");
    return 0;　　}