c++获取当前时间

time_t now = time(0);

    cout << "1970 到目前经过秒数:" << now << endl;

    tm *ltm = localtime(&now);
    char dateStr[100]={0};
    sprintf(dateStr,"%d%d%d%d%d%d",
            1900 + ltm->tm_year,
            1 + ltm->tm_mon,ltm->tm_mday,
            ltm->tm_hour,ltm->tm_min,ltm->tm_sec);
    cout<<"time:"<<dateStr<<endl;