QT日期计算

QString fileDateTime = QString("%0-%1-%2 00:00:00").arg(nowYear, 4, 10).arg(nowmon, 2, 10, QLatin1Char('0')).arg(nowday, 2, 10, QLatin1Char('0'));
QString endDateTime = QString("%0-%1-%2 00:00:00").arg(sYear, 4, 10).arg(smon, 2, 10, QLatin1Char('0')).arg(smday, 2, 10, QLatin1Char('0'));
QDateTime qFileDateTime = QDateTime::fromString(fileDateTime, "yyyy-MM-dd hh:mm:ss");
QDateTime qEndDateTime = QDateTime::fromString(endDateTime, "yyyy-MM-dd hh:mm:ss");
int days = qFileDateTime.daysTo(qEndDateTime);