On Saturday, August 22, 2015 3:26:56 PM hw wrote:
>
> Hi,
>
> I have the following in a perl script:
>
>
> if ($a != $b) {
> print "e: '$a', t: '$b'\n";
> }
>
>
> That will print:
>
> e: '69.99', t: '69.99'
>
>
> When I replace != with ne (if ($a ne $a) {), it doesn't print.
>
>
> Is that a bug or a feature? And if it's a feature, what's the explanation?
>
> And how do you deal with comparisions of variables when you get randomly
> either correct results or wrong ones? It's randomly because this
> statement checks multiple values in the script, and 69.99 is the only
> number showing up yet which isn't numerically equal to itself (but equal
> to itself when compared as strings).
>
Most languages have a decimal type that you should use when you need exact
math. I think for perl this is what you want:
http://search.cpan.org/~zefram/Math-Decimal-0.003/lib/Math/Decimal.pm
--
Fernando Rodriguez
