设计模式：中介者模式（C++实现）

在中介者模式中，中介者对象负责协调多个对象之间的交互，将对象之间的耦合度降低。

#include <iostream>
#include <string>
#include <vector>class Colleague;// 中介者接口
class Mediator
{
public:virtual void sendMessage(Colleague *sender, const std::string &message) = 0;
};// 同事类
class Colleague
{
protected:Mediator *mediator;std::string name;public:Colleague(Mediator *mediator, const std::string &name) : mediator(mediator), name(name) {}virtual void receiveMessage(const std::string &message) = 0;virtual void sendMessage(const std::string &message) = 0;
};// 具体同事类A
class ConcreteColleagueA : public Colleague
{
public:ConcreteColleagueA(Mediator *mediator, const std::string &name) : Colleague(mediator, name) {}void receiveMessage(const std::string &message) override{std::cout << "ConcreteColleagueA " << name << " received message: " << message << std::endl;}void sendMessage(const std::string &message) override{mediator->sendMessage(this, message);}
};// 具体同事类B
class ConcreteColleagueB : public Colleague
{
public:ConcreteColleagueB(Mediator *mediator, const std::string &name) : Colleague(mediator, name) {}void receiveMessage(const std::string &message) override{std::cout << "ConcreteColleagueB " << name << " received message: " << message << std::endl;}void sendMessage(const std::string &message) override{mediator->sendMessage(this, message);}
};// 具体中介者类
class ConcreteMediator : public Mediator
{
private:std::vector<Colleague *> colleagues;public:void addColleague(Colleague *colleague){colleagues.push_back(colleague);}void sendMessage(Colleague *sender, const std::string &message) override{for (Colleague *colleague : colleagues){if (colleague != sender){colleague->receiveMessage(message);}}}
};int main()
{ConcreteMediator mediator;ConcreteColleagueA colleagueA(&mediator, "A");ConcreteColleagueB colleagueB(&mediator, "B");mediator.addColleague(&colleagueA);mediator.addColleague(&colleagueB);colleagueA.sendMessage("Hello from A");colleagueB.sendMessage("Hi from B");return 0;
}

运行结果：

ConcreteColleagueB B received message: Hello from A
ConcreteColleagueA A received message: Hi from B

在上述代码中，Mediator是中介者接口，定义了发送消息的方法。Colleague是同事类，定义了接收消息和发送消息的方法。ConcreteColleagueA和ConcreteColleagueB是具体的同事类，实现了同事接口。ConcreteMediator是具体的中介者类，实现了中介者接口，并维护了同事对象的列表。在main函数中，我们创建了中介者对象和两个具体同事对象，并将同事对象添加到中介者中。然后，同事对象可以通过中介者来发送消息，并且中介者会将消息传递给其他同事对象。输出结果将显示同事对象之间的交互。