[Qt-interest] Cutting useless decimal places

[Atlant Schmidt]

Karl:

> ...better would be if Qt would provide me some function
> which just removes all 'unneeded zeros' on the right.

  In that case, I'd probably just sprintf() into a buffer
  and, looking at the result buffer from the right-most
  character towards the left, truncate all of the zeroes.

  This is one of those cases where it's trivially easy to
  implement a crude-but-100%-effective solution whereas
  you could spend a long time looking for an "elegant"
  solution (such as some already-defined method that
  does just what you want) ;-).

                      Atlant

-----Original Message-----
From: Karl Krach [mailto:mailinglists at blueSpirit.la]
Sent: Monday, October 25, 2010 15:26
To: Atlant Schmidt
Cc: qt-interest at trolltech.com
Subject: Re: [Qt-interest] Cutting useless decimal places

Hello Atlant,

I don't know if my translation into English is correct, but in physics
you differ between
  * valid digits and
  * decimal places.

You have implemented '4 valid digits'. This would be ok for me, but
better would be if Qt would provide me some function which just removes
all 'unneeded zeros' on the right.

      0.000125346     -> 0.000125346
      0.001253457     -> 0.001253457
      0.012534568     -> 0.012534568
      0.125345679     -> 0.125345679
      1.253456789     -> 1.253456789
      12.534567890    -> 12.53456789
      125.345678900   -> 125.3456789
      1253.456789000  -> 1253.456789
      12534.567890000 -> 12534.56789
      12534.567800000 -> 12534.5678
      12534.567000000 -> 12534.567
      12534.560000000 -> 12534.56
      12534.500000000 -> 12534.5
      12534.510000000 -> 12534.51
      12534.000000000 -> 12534

but also

      5.000000000     -> 5
      5.000100000     -> 5.0001

Maybe I will create something like this:

QString float2string(float number)
{
        return QString("%1").arg( number, 0, 'f' )
                             .remove( QRegExp("\\.?0*$") );
}

original:  "200.000000"
new:       "200"
original:  "20.000000"
new:       "20"
original:  "0.500000"
new:       "0.5"
original:  "0.125000"
new:       "0.125"
original:  "7000.000000"
new:       "7000"


Thanks,

Charly


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