Basic integer division in PHP is failing - Am clueless

Question

(Looks like something's wrong with my environment / system. Am analyzing it currently. Every logical answer was tried and it failed. So, will report back once I have more to share. Thanks for the answers!)

I have written some simple PHP code to calculate the duration between two dates, and do some basic arithmetic, to calculate some percentage value.

I am at a loss of clues on why this is not working! Seems to me that a variable is treated as an integer on one line and a string on another.

$start_DT = new DateTime($startdate); // e.g. 2011-06-07
$end_DT   = new DateTime($enddate);   // e.g. 2011-06-14
$today_DT = new DateTime("now");      // 2011-06-09

$duration       = date_diff($end_DT, $start_DT)->d;
$days_remaining = date_diff($end_DT, $today_DT)->d;

echo $days_remaining; // This outputs a value of "4" in my specific case
echo $duration;       // This outputs a value of "7" for my specific case. 

$percentage_dur_complete = $days_remaining / $duration;

echo $percentage_dur_complete; // This gives a value of NAN

// This line says that I am dividing my zero, to imply that 
// $duration might be a string. 
$percentage_dur_complete = $days_remaining / (float) $duration; 

Am I missing something basic? I am a relative newbie (2 months) to PHP. I really hope (with the risk of appearing stupid) that there's something I've missed out.

Thanks!

Answer 1

try

$percentage_dur_complete = (int)$days_remaining / (int)$duration;

EDIT: This works for me...

<?php 
$startdate = '2011-06-05';
$enddate = '2011-06-12';
$today_DT = new DateTime("now");
$start_DT = new DateTime($startdate); // e.g. 2011-06-07
$end_DT   = new DateTime($enddate);  
$duration       = date_diff($end_DT, $start_DT)->d;
$days_remaining = date_diff($end_DT, $today_DT)->d;
var_dump ($duration);
var_dump ($days_remaining);
$percentage_dur_complete = $days_remaining / $duration *100;
echo ($percentage_dur_complete);
?>

If it doesnt for you, it is most definitely an issue with your PHP installation/version!