What is the cleanest way to translate 42010958 Milliseconds to Hours:Minutes:Seconds in Qt?

Question

The QTime Class offers me a bit of a pickle insofar as it does not allow me to set milliseconds above certain values, thus making an entry like this invalid.:

    QTime time;
    time.setHMS(0,0,0,42010958); // I normally use a variable

Considering that the range of milliseconds I'm dealing with is between about 1000 and 1000000000, I'm not terribly keen on writing a tremendous amount of of integer conversion code to sanitise each entry, but I will do what I have to do.

What is the cleanest way to convert 42010958 Milliseconds into Hours:Minutes:Seconds in Qt?

`QTime time; time = time.addMSecs(42010958);` ? http://doc.qt.io/qt-5/qtime.html#addSecs — Robᵩ, Dec 02 '16 at 23:01
@Robᵩ You'd think so, but no. Same restrictions still apply. — Anon, Dec 02 '16 at 23:03
If the question was not strictly about Qt I would try to make up something with http://en.cppreference.com/w/cpp/chrono/duration — Alexander V, Dec 02 '16 at 23:37

score 6 · Accepted Answer · edited Dec 03 '16 at 00:23

6

"Cleanest" is a matter of taste, but here's how I would do it:

int milliseconds = 42010958;
int seconds      = milliseconds / 1000;
milliseconds     = milliseconds % 1000;
int minutes      = seconds / 60; 
seconds          = seconds % 60;
int hours        = minutes / 60;
minutes          = minutes % 60;

QTime time;
time.setHMS(hours, minutes, seconds, milliseconds);

edited Dec 03 '16 at 00:23

Anon

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answered Dec 02 '16 at 22:57

Jeremy Friesner

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Apart from that colon in there, this is a very clean and working solution. I'll give it a few minutes in case anyone knows of a function that makes this even cleaner. Otherwise I thank you. – Anon Dec 02 '16 at 23:05

thuga · Answer 2 · 2016-12-07T07:42:29.637

4

You can use QTime::fromMSecsSinceStartOfDay.

#include <QtCore>

int main(int argc, char *argv[])
{
    QTime time = QTime::fromMSecsSinceStartOfDay(42010958);
    qDebug() << time.toString("hh:mm:ss:zzz");
    return EXIT_SUCCESS;
}

edited Dec 07 '16 at 07:42

answered Dec 05 '16 at 07:48

thuga

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The `QCoreApplication` instance is unnecessary, and in an example you can use a single `` include :) – Kuba hasn't forgotten Monica Dec 05 '16 at 14:45
@KubaOber Woops, I just used the console application template when I made the example. – thuga Dec 07 '16 at 07:42

score 3 · Answer 3 · answered Dec 03 '16 at 01:31

3

You could use the STL.

using namespace std::chrono_literals;
auto milliseconds = 42010958ms;
auto seconds = std::chrono::duration_cast<std::chrono::seconds>(milliseconds);
milliseconds -= seconds;
auto minutes = std::chrono::duration_cast<std::chrono::minutes>(seconds);
seconds -= minutes;
auto hours = std::chrono::duration_cast<std::chrono::hours>(minutes);
minutes -= hours;

answered Dec 03 '16 at 01:31

Chris Ray

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2

+1 And add `#include "chrono_io.h" (https://howardhinnant.github.io/date/chrono_io.html)` if you want rock-solid debugging of your durations such as `std::cout << hours << '\n';` That will confirm that not only is the run-time value of `hours` is correct, but the *compile-time* type of `hours` is _also_ correct. :-) – Howard Hinnant Dec 03 '16 at 02:18
2

And people wonder why everyone looks outside of the standard library first. This kind of verboseness is rather sad in the design of a library meant for widespread reuse. – Kuba hasn't forgotten Monica Dec 05 '16 at 14:46

What is the cleanest way to translate 42010958 Milliseconds to Hours:Minutes:Seconds in Qt?

3 Answers3