Dominique Blas wrote:
> Sorry,
>
> I've found the following bug in mod_perl 1.25 and Perl 5.6.1.
> Maybe was it already released but in case not here it is :
>
> perl -e '
> $a=0.57;
> print sprintf("%03d", $a * 100)'
>
> prints "056" instead of "057"
>
> Same behaviour with $a=0,58 that prints "057".
>
> Of course it works for other values and also if you write
>
> $a=0,57*100;
> print sprintf("%03d", $a);
>
>
> Bug in sprintf() ?
No, this is not a bug. %d is the same as int(). Consider:
% perl -le '$a=0.57; print int ($a*100)'
56
Now read the manpage:
int EXPR
int Returns the integer portion of EXPR. If EXPR is
omitted, uses "$_". You should not use this func
tion for rounding: one because it truncates
towards "0", and two because machine representa
tions of floating point numbers can sometimes pro
duce counterintuitive results. For example,
"int(-6.725/0.025)" produces -268 rather than the
correct -269; that's because it's really more like
-268.99999999999994315658 instead. Usually, the
"sprintf", "printf", or the "POSIX::floor" and
"POSIX::ceil" functions will serve you better than
will int().
this explains the problem.
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Stas Bekman JAm_pH ------> Just Another mod_perl Hacker
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