Using 1 Class in Multiple Files

[Driklyn]

I'm trying to create a class inside a header file so that all my files can access that 1 class and only use that one. This is what I have so far.

----------

Window.h:

class Window
{
public:
Window();
~Window();

/* FUNCTIONS */
HWND OpenWindow(LPCTSTR, int, int);

/* VARIABLES */
int IsRunning;
};

typedef class Window *WINDOW;

----------

Main.h:

class Main
{
public:
Main();
~Main();

WINDOW GameWindow;
};

Main::Main()
{
Main::GameWindow = new Window();
}

typedef class Main *MAIN;

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The above code works and lets me call Main::GameWindow in every file but that's as far as I can go. I can't call Main::GameWindow->OpenWindow(). How do I fix this?