Where can I define the body for a private function?

Question

I have a header like this (header guards not shown):

class GameSystem
{
public:
    GameSystem(Game *pcGame);
    virtual ~GameSystem();
    void Setup();
private:
    void InitGame();
    void RunGame();
    void ExitGame();
    Game *m_pcGame;

    /* Properties */
    int m_nWidth;
    int m_nHeight;
    int m_nFps;
    bool m_bFullscreen;
};

Where can I define the body for InitGame(), RunGame() and ExitGame()? Can I define it in my .cpp file? If so, how? Or am I obliged to make their body in my .h file?

I'm using Eclipse and I began typing: void GameSystem:: and then it doesn't suggest the private functions.

Answer 1

Yes, you can define then in a .cpp file. Just put #include "MyHeader.h" at the beginning of the file. You'll also need to start each function like so

void GameSystem::Init(){
     //stuff
}

Answer 2

Generally you would define both public and private functions in the .cpp file.

One reason to define functions in the .h file is if you want them to be inlineable.