学步园

#include <iostream>
using namespace std;

//
struct IMeditor;

struct IPerson
{
public:
	IPerson() : m_pMeditor(NULL) { }
	virtual ~IPerson() { }

	void SetMeditor(IMeditor *pMeditor) { m_pMeditor = pMeditor; }
	virtual void SendMessage(string message) = 0;
	virtual void RecvMessage(string message) = 0;

protected:
	IMeditor *m_pMeditor;
};

struct IMeditor
{
public:
	IMeditor(IPerson *pRenter, IPerson *pLandlord) : m_pRenter(pRenter), m_pLandlord(pLandlord) { }
	virtual ~IMeditor() { }

	virtual void SendMessage(string message, IPerson *pPerson) = 0;

protected:
	IPerson *m_pRenter, *m_pLandlord;
};

class CRenter : public IPerson
{
public:
	CRenter() { }
	virtual ~CRenter() { }

	virtual void SendMessage(string message) { m_pMeditor->SendMessage(message,this); }
	virtual void RecvMessage(string message) { cout<<"租房者收到信息："<<message.c_str()<<endl; }
};

class CLandlord : public IPerson
{
public:
	CLandlord() { }
	virtual ~CLandlord() { }

	virtual void SendMessage(string message) { m_pMeditor->SendMessage(message,this); }
	virtual void RecvMessage(string message) { cout<<"房东收到信息："<<message.c_str()<<endl; }
};

class CHouseMeditor : public IMeditor
{
public:
	CHouseMeditor(IPerson *pRenter, IPerson *pLandlord) : IMeditor(pRenter,pLandlord) { }
	virtual ~CHouseMeditor() { }

	virtual void SendMessage(string message, IPerson *pPerson)
	{
		if(m_pRenter == pPerson)
			m_pLandlord->RecvMessage(message);
		else
			m_pRenter->RecvMessage(message);
	}
};

//
void main()
{
	CRenter renter;
	CLandlord landlord;

	CHouseMeditor houseMeditor(&renter,&landlord);

	renter.SetMeditor(&houseMeditor);
	landlord.SetMeditor(&houseMeditor);

	renter.SendMessage("求租房子。");
	landlord.SendMessage("出售房子。");
}