toDouble() lost the data

iskenderoguz

I get data from database with this

query.value(0).toString();

after that I convert string to double

query.value(0).toString().toDouble();

But I lost my data

Original data is 123.45
but after toDouble() data is 123.5

How can I fix this ?

SGaist

Hi,

Are you sure that your string contains 123.45 ?

iskenderoguz

yes I am sure

SGaist

Just tested with:

QString test("123.45");
qDebug() << test.toDouble() << test.toFloat();

And got the right results.

iskenderoguz

yes your code work but my problem still exists


qDebug()<<query.value(0).toString()<<" - "<<query.value(0).toDouble()<<" - "<<query.value(0).toString().toDouble();

"123.45" - 123.5 - 123.5

iskenderoguz

Also I tested this

QString test(query.value(0).toString());
qDebug() << test << test.toDouble() << test.toFloat();

"123.45" 123.5 123.5

JKSH

You did not lose any data. qDebug() simply displays 4 significant figures by default.

Test this:

qDebug() << (test.toDouble() - 123.5) // Should produce -0.05

Also, you can ask it to display more significant figures:

qDebug() <<  qSetRealNumberPrecision(10) << test << test.toDouble() << test.toFloat();