const std::string getCurrentSystemTime(){  auto tt = std::chrono::system_clock::to_time_t  (std::chrono::system_clock::now());  struct tm* ptm = localtime(&tt);  char date[60] = {0};  sprintf(date, "%d-%02d-%02d      %02d:%02d:%02d",    (int)ptm->tm_year + 1900,(int)ptm->tm_mon + 1,(int)ptm->tm_mday,    (int)ptm->tm_hour,(int)ptm->tm_min,(int)ptm->tm_sec);  return std::string(date);}