Visual C++ 파일 열기 다이얼로그 API

char szFile[256];
  //API file dialog
  OPENFILENAMEA ofn;
  ZeroMemory(&ofn, sizeof(ofn));
  ofn.lStructSize = sizeof(ofn);
  ofn.hwndOwner = NULL;
  ofn.lpstrFile = szFile;
  ofn.lpstrFile[0] = '\0';
  ofn.nMaxFile = sizeof(szFile);
  ofn.lpstrFilter = "All\0*.*\0Map\0*.map\0";
  ofn.nFilterIndex = 1;
  ofn.lpstrFileTitle = NULL;
  ofn.nMaxFileTitle = 0;
  ofn.lpstrInitialDir = NULL;
  ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
  BOOL ret = GetOpenFileNameA(&ofn);
  if (ret) {
   // load map and enter training mode
  }