Rounding problem

Hi,

I'm using PHP 4.4.4. I'm confused about the function "round". I have

<?= "prov tax: $provincial_tax " . round($provincial_tax, 2) . "<BR>
\n" ?>

When $provincial_tax = 7.185, the output above is

prov tax: 7.185 7.18

Shouldn't the second number be 7.19 since 7.185 rounds to 7.19? I
appreciate any insights you may have, - Dave

re: Rounding problem

laredotornado@zipmail.com wrote:<?php
$provincial_tax = 7.185;
$provtax = round($provincial_tax, 2);
echo $provtax;
?>

I ran that in DzSoft PHP Editor 4.1.2. and it gave me 7.19, then I ran it on
my server running PHP version 5.2.5 and it gave 7.19 so what's the problem?
Maybe it's the PHP version.

Paul
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re: Rounding problem

laredotornado@zipmail.com wrote:This has been discussed many times in this forum, and it has to do with
the internal representation of floating point numbers in the hardware.
7.185 is a repeating decimal (like 1/3 is in decimal) and cannot be
represented exactly.

The value is probably not 7.185, but something like 7.184999999345.
Printed, it shows 7.185. But rounding will take it to 7.184, which is
correct. If you want to round to 7.185, you have to add a fudge factor,
i.e.
round($provincial_tax + 0.0001);

Or do everything using integers and only change it when you go to display.



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Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
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re: Rounding problem

laredotornado@zipmail.com wrote:7.185 does not 'round' either way..its a 50-50 choice to round it up or
down.