C++ 打印当前时间

//打印当前时间
string warn_export::timetoStr(){
    char tmp[64];
    time_t t = time(NULL);
    tm *_tm = localtime(&t);
    int year  = _tm->tm_year+1900;
    int month = _tm->tm_mon+1;
    int date  = _tm->tm_mday;
    int hh = _tm->tm_hour;
    int mm = _tm->tm_min;
    int ss = _tm->tm_sec;
    sprintf(tmp,"%04d%02d%02d%02d%02d%02d%02d%02d",
            year,month,date,hh-1,0,0,year,month,date,hh,mm,ss);
    return string(tmp);
}

//打印指定时间
string warn_export::timetoStr(long timeStamp){
    time_t t = timeStamp;
    tm *_tm = gmtime(&t);
    int year  = _tm->tm_year+1900;
    int month = _tm->tm_mon+1;
    int date  = _tm->tm_mday;
    int hh = _tm->tm_hour;
    //int mm = _tm->tm_min;
    //int ss = _tm->tm_sec;
    char tmp[64];
    sprintf(tmp,"%04d-%02d-%02d（%02d:%02d:%02d - %02d:%02d:%02d）",
            year,month,date,hh-1,0,0,hh,0,0);
    return string(tmp);
}