Posted by Anthony Tippett on 04/05/05 03:07

Ok i've narrowed it down a little bit but still can't figure it out..

Here's the code and what I get for the output. Does anyone know what's
going on? Can someone else run it on their computer and see if they get
the same results?
<?php

$a = "17.00" * "1";
$a+= "1.10" * "1";
$a+= "0.32" * "1";
$a+= "0.07" * "1";

print $a."<br>"; // 18.49

var_dump($a); // float(18.49)
var_dump($a-18.49); // float(3.5527136788005E-15)
?>


Anthony Tippett wrote:
> I'm having trouble figuring out why subtraction of two floats are giving
> me a very small number. I'm thinking it has something to do with the
> internals of type casting, but i'm not sure. If anyone has seen this or
> can give me some suggestions, please.
>
> I have 2 variables that go through a while loop and are
> added/subtracted/ multipled. InvAmt and InvPay are shown as
> floats but when they are subtracted, they give me a really small
> number
>
> // code
> var_dump($InvAmt);
> var_dump($InvPay);
> var_dump($InvAmt-$InvPay);
>
> // output
> float(18.49)
> float(18.49)
> float(2.1316282072803E-14)
>

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