Why does 15.5 mod 5 = 0?

Question

I understand 15 mod 5 = 0 because there is no remainder from the division.

But why does 15.5 mod 5 == 0 also? Isn't there .5 remaining?

$time = "15.5";
$interval = 5.0;
if($time % $interval == 0)
    echo "it's time!";
else
    echo "not time";

//Outputs: it's time!

@Thilo Appears to be PHP from the URL example ... – HeatfanJohn Jul 16 '12 at 01:24 — HeatfanJohn, Jul 16 '12 at 01:24

Elliot Bonneville · Accepted Answer · 2012-07-16T01:29:55.100

17

From the PHP docs:

Operands of modulus are converted to integers (by stripping the decimal part) before processing.

Use fmod if you want to preserve decimal remainders. (Thanks for the link, Oli Charlesworth, wasn't aware that such a function existed.)

edited Jul 16 '12 at 01:29

answered Jul 16 '12 at 01:24

Elliot Bonneville

7

@KevinDuke: It doesn't suck that much. Use [`fmod`](http://www.php.net/manual/en/function.fmod.php) instead. – Oliver Charlesworth Jul 16 '12 at 01:26
@KevinDuke: I just typed in "modulus decimal". I'm no PHP expert either. I just use Google a lot. :) – Elliot Bonneville Jul 16 '12 at 01:31

1 Answers1