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Postings from October 2003
On Tue, Oct 07, 2003 at 08:53:06PM +0200, Tels <perl_dummy@bloodgate.com> wrote:
> POSIX::floor () converts the 81 as result to 80, as does int().
> sprinf("%.0f"), OTOH, converts this fine to 81, but it
> fails for things like 9.91234 - this should be truncated to 9, but sprintf
> rounds it to 10.
sprintf is supposed to round, not truncate (though "in an
implementation-defined manner").
> Here is a case where the new sprintf("%.0f") fails, but the former int()
> works:
>
> # perl -Mbigint -le 'print 9999->broot()'
> 99
> # perl -Ilib -Mbigint -le 'print 9999->broot()'
> 100
>
> And here is one where the old one fails, but the new one works:
>
> # perl -Mbigint -le 'print +(81 ** 3)->broot(3)'
> 80
> # perl -Ilib -Mbigint -le 'print +(81 ** 3)->broot(3)'
> 81
If you want to truncate, but allow slight wiggle-room for error in the
lowest 1-3 bits, try something like:
$result = "$result" if $result !~ /./;
or use an explicit ratio-to-nearest-integer check:
$result = floor($result+.5) if abs($result/floor($result+.5)) < 1e-14