extern BOOL CreateDlgControls(
  HWND hWnd,
  HWND hwndParent,  // should be NULL for top-level window
  LPCTSTR res_id,
  HINSTANCE hInst,
  BOOL fResize=TRUE);

extern BOOL CenterWindow(HWND hwndChild, HWND hwndParent);

extern WORD myrand(void);
extern void mysrand(void);

extern void DeleteAllChildWindows(HWND hwnd);