Substract two QString values

[Alberto]

Hi,
I´m trying to substract two hours.
QString hour_1 = "11:00";
QString hour_2 = "10:00";

I would like to save the result from (11:00 - 10:00) into another QString.

¿Does anyone know how could I do this?

Thanks for replying!

[SGaist]

Hi,

Do you mean

QString result = hour_1 + " - " + hour_2;

?

[Gruzzyh2]

Hey,

I think that you want to compute the difference between the two timestamps ?
Take a look at QTime (http://doc.qt.io/qt-5/qtime.html) and don't use QString. I think you should try to use a suitable type for your var.
Two solutions :

• Either you get a time from QString so you can try something like this :

// Time in QString
QString sHour_1 = "11:00";
QString sHour_2 = "10:00";

// Time in QTime from QString
QTime hour_1 = QTime::fromString(sHour_1, "hh:mm");
QTime hour_2 = QTime::fromString(sHour_2, "hh:mm");

// hour_2 in seconds to substracts from hour_1
int secs = hour_2.second();

QTime result = hour_1.addSecs(-secs); // minus 'cause secs is positive

result.toString("hh:mm"); // will get you a QString "01:00"

• Or you could have taken the times in QTime from the beginning :

QTime hour_1 (11, 0, 0);
QTime hour_2 (10, 0, 0);

Then you do the same as above.

Gruz

[Alberto]

I did this:

QTime hour_1 = QTime::fromString(sHour_1,"hh:mm");
QTime hour_2 = QTime::fromString(sHour_2,"hh:mm");

qDebug()<<hour_2;

int secs = hour_2.second();

qDebug()<<secs;

QTime result = hour_1.addSecs(-secs);
QString result2 =result.toString("hh:mm");

qDebug()<<result;
qDebug()<<result2;

But the result obtained is this:
"11:00"
"10:00"
QTime("10:00:00.000")
0
QTime("11:00:00.000")
"11:00"

Sorry for my English.

[Gruzzyh2]

Can you match every qDebug with the line please ?
(np for the english mine is bad too)

[Alberto]

@Gruzzyh2

qDebug()<<sHour_1;
"11:00"

qDebug()<<sHour_2;
"10:00"

qDebug()<<hour_2;
QTime("10:00:00.000")

qDebug()<<secs;
0

qDebug()<<result;
QTime("11:00:00.000")

qDebug()<<result2;
"11:00"

[SGaist]

A more simpler solution:

    QTime time1 = QTime::fromString("11:00", "HH:mm");
    QTime time2 = QTime::fromString("10:00", "HH:mm");

    qDebug() << QTime::fromMSecsSinceStartOfDay(time2.msecsTo(time1));