View Full Version : very small qreal number
dreamer
24th June 2008, 10:02
How can i disable the exponential notation? for example, if i get the topleft corner(QPointF) of a QGraphicsrectitem i couldn't have this kind of result:
QPointF(-1.06581e-14,12); but QPointF(-0.000000000"...",12); where the x coordinate is truncated at the ith position.....
caduel
24th June 2008, 10:57
You did not tell us, how you want to output that stuff... we have to guess what your problem is.
Anyway, have a look at QTextStream::setRealNumberNotation
HTH
dreamer
24th June 2008, 11:03
I read and generate number with a QTextstream so i use this code to resolve the problem:
QTextStream out("some file");
out.setRealNumberPrecision ( 5 );
The default real number precision is '6' that put in some case, the exponential "e" notation........setting it on '5' it doesn't appear.......
Is it just a case or is there a reason??
caduel
24th June 2008, 11:33
A clear case of "read the docs".
The default for QTextStream::setRealNumberNotation is QTextStream::SmartNotation.
(Checked the source...)
TextStream::SmartNotation => Scientific or fixed-point notation, depending on which makes most sense (printf()'s %g flag).
So, the answer "why" your code behaves like it does is probably given by "man 2 printf".
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