qt c++ “QString::number” not retaining decimal places needed

Question

I'm having trouble converting numbers to strings and retaining all of the decimal places. In the code below, both flat and flon are declared as double and have 6 decimal places (flat = 32.447134), (flon = -100.136468). After converting with QString::number, (flat = 32.4471), and (flon = -100.136). These are gps coordinates so it is very important to keep all of the decimal places.

If I shorten flon to -99.136468, it retains 4 decimal places after conversion, so it appears that there must be a limit to the length of the string of 8 characters. I need 11.

How can I convert them and retain all f the decimal places?

I have tried "QString::number(long n, int base = 10)" and others from the QT documentation but get syntax and other errors when I try to run.

Thanks in advance!

if (ui -> northeast -> isChecked())
       {
           flat = flat + .00007;
           flon = flon + .00007;
           lo = QString::number(flon);
           la = QString::number(flat);

           QString ll = la + "," + lo;
           ui -> gps_latlon -> setText(ll);
      }

Answer 1

You are using this overload of QString::number :

QString QString::number(double n, char format, int precision)

So pass the correct format and your required precision.

Do it like this:

str = QString::number(flat, 'f', 6);

And if you're wondering what f means, check it out here .