QTextStream question

[JonB]

@qAlexKo
If your combination of qSetPadChar('0') << qSetFieldWidth(2) does not do it I am not sure. Could you show just what output you do get with your code? (Yours probably wouldn't be quite right though, even if it worked on the integers, because your "." field would also get these, wouldn't it?)

[qAlexKo]

@JonB said in QTextStream question:

. Could you show just what output you do get with your code?

010.020

[JonB]

@qAlexKo
Your reply crossed with my update. At least one of those 0s is (unfortunately) for the . field. Start by getting rid of that to see what is going on. And another 0 may be from the << Qt::endl? I think you have those for each <<. You are getting something like (with spacing so we can read):

01  0.  02  0\n

[qAlexKo]

@JonB said in QTextStream question:

At least one of those 0s is (unfortunately) for the . field

    int a=1;
    cout << qSetPadChar('0') << qSetFieldWidth(2)  << a << Qt::endl;

Output: 010

[JonB]

@qAlexKo Like I said, remove << Qt::endl?

[JonB]

@qAlexKo
If/when this does not get you quite what you want, or it's too difficult/fiddly/messy. Since you only want those options against (single digit) integers, but they will like affect everything on the stream, I would use QString::number() or other of QString numeric formatting methods to produce desired number format and send that as a string rather then fiddling with QTextStream formatting directives.

[qAlexKo]

@JonB said in QTextStream question:

@qAlexKo Like I said, remove << Qt::endl?

Yes, the last cout << Qt:endl is to blame.

    int a=1;
    cout << "test" << Qt::endl;
    cout << qSetPadChar('0') << qSetFieldWidth(2) << a;
    //cout << Qt::endl;

If I stream to QTextStream everything is OK

    QString qstr;
    QTextStream qstream(&qstr);
    int aa=1;
    qstream << qSetPadChar('0') << qSetFieldWidth(2) << aa;
    cout << qstr << Qt::endl;

[JonB]

@qAlexKo
Yes, I thought so. See my latest message: for simplicity I suggest you do your formatting work to produce your desired string and then send that to the text stream. Looks simpler.

[qAlexKo]

@JonB said in QTextStream question:

Looks simpler

In the full variant "01.02" it is important to set zero width for "." output.

    QString qstr;
    QTextStream qstream(&qstr);
    int aa=1, bb=2;
    qstream << qSetPadChar('0') << qSetFieldWidth(2) << aa << qSetFieldWidth(0) << "." << qSetFieldWidth(2) << bb;
    cout << qstr << Qt::endl;

[JonB]

@qAlexKo said in QTextStream question:

In the full variant "01.02" it is important to set zero width for "." output.

So? I would build a string for the whole of 01.02, or for each number separately with a "." field and set the "gap" between fields to zero/empty. Up to you.

[qAlexKo]

@JonB

The variant with cout also works if do this:

    QTextStream cout(stdout);
    int a=1, b=2;
    cout << qSetPadChar('0') << qSetFieldWidth(2) << a << qSetFieldWidth(0) << "." << qSetFieldWidth(2) << b << qSetPadChar(0) << Qt::endl;

[JoeCFD]

@qAlexKo you can create one QString with arg.

    int a = 1;
    int b = 2;

    std::cout << qPrintable( QString( "%1." ).arg( a, 2, 10, QChar( '0' ) ) ) 
              << qPrintable( QString( "%1" ).arg( b, 2, 10, QChar( '0' ) ) ) << std::endl;

[JonB]

@qAlexKo said in QTextStream question:

The variant with cout also works if do this:

Yes, which is why I wrote earlier that persisting to do it this way gets "difficult/fiddly/messy" and that using a QString method like number() or arg() seems so much easier. I can't keep repeating the same thing so I have said my piece now.

[JoeCFD]

@JonB Agree!

[qAlexKo]

@JoeCFD said in QTextStream question:

std::cout << qPrintable( QString( "%1." ).arg( a, 2, 10, QChar( '0' ) ) ) 
          << qPrintable( QString( "%1" ).arg( b, 2, 10, QChar( '0' ) ) ) << std::endl;

Compare your statement with mine if I define a simple macro:
#define co(width, what) qSetPadChar('0') << qSetFieldWidth(width) << what << qSetFieldWidth(0)

Then: "01.02" output is much simpler:
cout << co(2,a) << co(0,'.') <<co(2, b) << Qt::endl;