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$n * 1000 and Mod

I've been using fmod to validate data entry in Terry's Turkeys. You need to check weights are entered in 5g increments. So i take the input, *1000 and take the modulus for 5.

This threw up an odd bug when i inputted 8.065kg. Perfectly valid, as you can see. But rejected by my code. So i did a test:

for ($n = 0; $n < 10; $n += 0.005)

{

        $largen = $n*1000;

        $mod = $largen % 5;

        if (fmod(($largen), 5) != 0 || $largen % 5 != 0) 

        { 

                echo "<tr><td>$n</td><td>$largen</td><td>".fmod(($largen), 5)."</td><td>".$mod."</td></tr>";

        }

You'll find the output rather odd: Results

Why's it doing this? It's not just fmod() being weird as it's for floating points, but % too.

Hope you get this working, mate.

Oh, and could you put borders on that table? It's hard to read.

EDIT: Got it:

$n = round($n, 5);

Yeah, the trouble is that although it's an integer, it's an integer stored in a floating point variable and you can't use modulo with floating point, even if it happens to contain an integer value.