QTextStream question

[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;