how to deal with numbers containing a comma?

Natural_Bugger

Hi, as a follow up on another topic a new issue arose.
https://forum.qt.io/topic/108209/qlineedit-autofill/13.

the following operation returns sometimes fractal numbers containing a comma.

...... (baseNumber/1000000.0);

i can't do further operations depending on the results of the code above.
"0,00012", does not further compute
"1e-05", does further compute.

do you need to use signed variables?
special measurements when handling big numbers?

how to turn "1e-05" this into "0,0001" again?

JonB

@Natural_Bugger
Have you looked at https://doc.qt.io/qt-5/qstring.html#argument-formats ? I suspect you want f format, the default is probably g? And if you have commas in your input/output, look at the locale you are using.

Natural_Bugger

@JonB

thnx for your pront reply:

the main problem is that i can do further computing on numbers containing a comma, the results of the equation above, before putting it back into a a QLineEdit form field.
"inf" shows up in the QlineEdit form field.

JonB

@Natural_Bugger
Yes, you need to convert (comma) string representation back to the actual number (float/double) before you can do computations on it.

Natural_Bugger

@JonB

this is what is what i do.

    float solution = 0.0;
    QString one = ui->lineEdit_1->text();
    float floatOne = one.toFloat();
    QString two = ui->lineEdit_2->text();
    float floatTwo = twor.toFloat();

    solution = 1/(2 * M_PI * floatOne * floatTwo); // it stalls here.
    ui->lineEdit_3->->setText(QString::number(solution, 'f', 10));

this occurs after operation from the other thread.

jsulm

@Natural_Bugger said in how to deal with numbers containing a comma?:

this occurs after operation from the other thread

What does this other thread do?
Does it access UI?

JonB

@Natural_Bugger
Apart from what @jsulm asks you...

...QString::toFloat() won't tell you if it succeeds. You need to pass in the &ok parameter and check that, see the docs. Plus docs tell you

The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toFloat()

For historical reasons, this function does not handle thousands group separators. If you need to convert such numbers, use QLocale::toFloat().

SGaist

Hi,

Why not use QSpinBox and/or QDoubleSpinBox ?

That way you don't need to go back and forth with strings.

Natural_Bugger

@jsulm

thnx for your reply.

sorry, i meant the forum thread: link text