Log ObServer example

LogObserver_Example.cpp

#include <list>        
#include <stdio.h>
#include <stdarg.h>
#include <Windows.h>

class CObServer 
{
public:
	virtual void notify(std::string log) {};
};

bool m_status;

class CLogConsole : public CObServer
{
protected:
	static void worker()
	{
		AllocConsole();

		do {
			Sleep(1);
		} while (m_status);
	};


public:

	CLogConsole()
	{
		DWORD dwId;

		m_status = true;

		CreateThread(0, 0, (LPTHREAD_START_ROUTINE)CLogConsole::worker, 0, 0, &dwId);
	};

	~CLogConsole()
	{
		m_status = false;
	};

	void notify(std::string log)
	{
		DWORD dwBytesWritten;
		HANDLE Handle = GetStdHandle(STD_OUTPUT_HANDLE);

		WriteFile(Handle, log.c_str(), log.length(), &dwBytesWritten, NULL);
	};
};



class CLog
{
protected:
	std::list<CObServer *> m_obServers;

	void notifyObservers(std::string log)
	{
		for (std::list<CObServer *>::iterator it = m_obServers.begin(); it != m_obServers.end(); it++) {
			(*it)->notify(log);
		}
	};

public:
	void attach(CObServer * obServer)
	{
		m_obServers.push_back(obServer);
	};

	void deattach(CObServer * obServer)
	{
		m_obServers.remove(obServer);
	};

	void write(char * szFormat, ...)
	{
		static char szTemp[1024];

		memset(szTemp, 0, sizeof(szTemp));

		va_list args;
		va_start(args, szFormat);
		vsprintf_s(szTemp, szFormat, args);
		va_end(args);

		notifyObservers(szTemp);
	};
};

int main()
{
	CLog gLog;
	CLogConsole gLogConsole;

	gLog.attach(& gLogConsole);

	gLog.write("%s", "test");


	system("pause");

    return 0;
}