QString:number with maximum 2 decimal places without trailing zero

Neaţu Ovidiu Gabriel picture Neaţu Ovidiu Gabriel · Jul 22, 2014 · Viewed 31.5k times · Source

I have a division like this:

number / 1000.0

Sometimes it gives answers like 96.0000000001, sometimes the division works as expected.

I want to limit my number to a maximum of two decimal places and without trailing zeros.

If it's 96.5500000001 it should show 96.55.

If it's 96.4000000001 it should show 96.4

It is possible to format a string in this way?

I've checked the documentation and it provides 'f' argument for specifying the number of the decimal places but this way the trailing zeros remain. This is what I have tried:

QString::number(number / 1000.0, 'f', 2)

But this gives me for 96.4000000001 --> 96.40 instead of 96.4

Any solution? How can I format in this way?

Answer

lpapp picture lpapp · Jul 22, 2014

The documentation is pretty clear about what you should do:

A precision is also specified with the argument format. For the 'e', 'E', and 'f' formats, the precision represents the number of digits after the decimal point. For the 'g' and 'G' formats, the precision represents the maximum number of significant digits (trailing zeroes are omitted).

Therefore, use either the 'g' or 'G' format.

main.cpp

#include <QString>
#include <QDebug>

int main()
{
    qDebug() << QString::number(96400.0000001 / 1000.0, 'g', 5);
    qDebug() << QString::number(96550.0000001 / 1000.0, 'G', 5);
    return 0;
}

main.pro

TEMPLATE = app
TARGET = main
QT = core
SOURCES += main.cpp

Build and Run

qmake && make && ./main

Output

"96.4"
"96.55"