src_corelib_time_qdatetime.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
QDate d1(1995, 5, 17);  // May 17, 1995
QDate d2(1995, 5, 20);  // May 20, 1995
d1.daysTo(d2);          // returns 3
d2.daysTo(d1);          // returns -3
 
 
QDate date = QDate::fromString("1MM12car2003", "d'MM'MMcaryyyy");
// date is 1 December 2003
 
 
QDate date = QDate::fromString("130", "Md"); // invalid
 
 
QDate::fromString("1.30", "M.d");           // January 30 1900
QDate::fromString("20000110", "yyyyMMdd");  // January 10, 2000
QDate::fromString("20000110", "yyyyMd");    // January 10, 2000
 
 
QDate::isValid(2002, 5, 17);  // true
QDate::isValid(2002, 2, 30);  // false (Feb 30 does not exist)
QDate::isValid(2004, 2, 29);  // true (2004 is a leap year)
QDate::isValid(2000, 2, 29);  // true (2000 is a leap year)
QDate::isValid(2006, 2, 29);  // false (2006 is not a leap year)
QDate::isValid(2100, 2, 29);  // false (2100 is not a leap year)
QDate::isValid(1202, 6, 6);   // true (even though 1202 is pre-Gregorian)
 
 
QTime n(14, 0, 0);                // n == 14:00:00
QTime t;
t = n.addSecs(70);                // t == 14:01:10
t = n.addSecs(-70);               // t == 13:58:50
t = n.addSecs(10 * 60 * 60 + 5);  // t == 00:00:05
t = n.addSecs(-15 * 60 * 60);     // t == 23:00:00
 
 
QTime time = QTime::fromString("1mm12car00", "m'mm'hcarss");
// time is 12:01.00
 
 
QTime time = QTime::fromString("00:710", "hh:ms"); // invalid
 
 
QTime time = QTime::fromString("1.30", "m.s");
// time is 00:01:30.000
 
 
QTime::isValid(21, 10, 30); // returns true
QTime::isValid(22, 5,  62); // returns false
 
 
QDateTime now = QDateTime::currentDateTime();
QDateTime xmas(QDate(now.date().year(), 12, 25).startOfDay());
qDebug("There are %d seconds to Christmas", now.secsTo(xmas));
 
 
QTime time1 = QTime::fromString("131", "HHh");
// time1 is 13:00:00
QTime time1 = QTime::fromString("1apA", "1amAM");
// time1 is 01:00:00
 
QDateTime dateTime2 = QDateTime::fromString("M1d1y9800:01:02",
                                            "'M'M'd'd'y'yyhh:mm:ss");
// dateTime is 1 January 1998 00:01:02
 
 
QDateTime dateTime = QDateTime::fromString("130", "Mm"); // invalid
 
 
QDateTime dateTime = QDateTime::fromString("1.30.1", "M.d.s");
// dateTime is January 30 in 1900 at 00:00:01.
dateTime = QDateTime::fromString("12", "yy");
// dateTime is January 1 in 1912 at 00:00:00.
 
QDateTime startDate(QDate(2012, 7, 6), QTime(8, 30, 0));
QDateTime endDate(QDate(2012, 7, 7), QTime(16, 30, 0));
qDebug() << "Days from startDate to endDate: " << startDate.daysTo(endDate);
 
startDate = QDateTime(QDate(2012, 7, 6), QTime(23, 55, 0));
endDate = QDateTime(QDate(2012, 7, 7), QTime(0, 5, 0));
qDebug() << "Days from startDate to endDate: " << startDate.daysTo(endDate);
 
qSwap(startDate, endDate); // Make endDate before startDate.
qDebug() << "Days from startDate to endDate: " << startDate.daysTo(endDate);
 
QDateTime local(QDateTime::currentDateTime());
QDateTime UTC(local.toTimeSpec(Qt::UTC));
qDebug() << "Local time is:" << local;
qDebug() << "UTC time is:" << UTC;
qDebug() << "No difference between times:" << local.secsTo(UTC);
 
QDateTime UTC(QDateTime::currentDateTimeUtc());
QDateTime local(UTC.toLocalTime());
qDebug() << "UTC time is:" << UTC;
qDebug() << "Local time is:" << local;
qDebug() << "No difference between times:" << UTC.secsTo(local);
 
QDateTime local(QDateTime::currentDateTime());
QDateTime UTC(local.toUTC());
qDebug() << "Local time is:" << local;
qDebug() << "UTC time is:" << UTC;
qDebug() << "No difference between times:" << local.secsTo(UTC);
 
QDateTime local(QDateTime::currentDateTime());
qDebug() << "Local time is:" << local;
 
QDateTime UTC(local);
UTC.setTimeSpec(Qt::UTC);
qDebug() << "UTC time is:" << UTC;
 
qDebug() << "There are" << local.secsTo(UTC) << "seconds difference between the datetimes.";
 
QString string = "Monday, 23 April 12 22:51:41";
QString format = "dddd, d MMMM yy hh:mm:ss";
QDateTime invalid = QDateTime::fromString(string, format);
 
QString string = "Tuesday, 23 April 12 22:51:41";
QString format = "dddd, d MMMM yy hh:mm:ss";
QDateTime valid = QDateTime::fromString(string, format);
 
// 23 April 2012:
QDate date = std::chrono::year_month_day(std::chrono::year(2012),
                                         std::chrono::month(4),
                                         std::chrono::day(23));
 
// Same, under `using std::chrono` convenience:
QDate dateWithLiterals1 = 23 / April / 2012y;
QDate dateWithLiterals2 = 2012y / April / 23;
 
// Last day of February 2000
QDate lastDayFeb2020 = 2000y / February / last;
 
// First Monday of January 2020:
QDate firstMonday = 2020y / January / Monday[0];
 
// Last Monday of January 2020:
QDate lastMonday = 2020y / January / Monday[last];
 
QDateTime local(QDateTime::currentDateTime());
QDateTime UTC(local.toTimeSpec(QTimeZone::UTC));
qDebug() << "Local time is:" << local;
qDebug() << "UTC time is:" << UTC;
qDebug() << "No difference between times represented:" << local.secsTo(UTC);