Subtracting time help

Anon

I need to subtact time and am getting nowhere fast. The time is passed from a form and in the format $start_hour, $start_minutes, and $start_ampm (where it could be "am" or "pm"). I also have $end_* variables for the end time. If the end time is pm I add 12 hours to it and subtract the start time from the end time.
My problem is the hours almost never come out correctly. Here is some example code that I have been testing with to illustrate the issue.

<?php
echo "Time test<br>\n";
$start_hour="8";
$start_minutes="30";
$end_hour="8";
$end_minutes="35";
$start_ampm="am";
$end_ampm="am";

echo "start: $start_hour:$start_minutes $start_ampm<br>\n";
echo "end: $end_hour:$end_minutes $end_ampm<br>\n";

// addition of 12 left out since I am only testing am stuff at the moment
$begin=gmmktime($start_hour,$start_minutes,"0","1","3","2000");
$end=gmmktime($end_hour,$end_minutes,"0","1","3","2000");
$result=gmdate("g:i",$end-$begin);

echo "Result is $result";
?>

And here is what I get back:
Time test
start: 8:30 am
end: 8:35 am
Result is 12:05

Any ideas?

Brian
PS this is on Linux and running PHP 4.0.1pl2

Anon

the fact that the answer's out by 12 hours and you're adding 12 hours at some point leads me to suspect that your am/pm script may have a bug ;-)

--
rad

Anon

gmdate's second parameter is a timestamp, and you are passing in the difference between two timestamps. The result of gmdate is a whole date, and you are getting the correct answer: Jan 1, 1970, 12:05 am.

Since you want something like 00:05, I would suggest you use "G:i" as the formatting string. Note that it won't work for time differences larger than 24 hours.

Anon

The capital 'G' worked like a charm! Thanks!

Brian

Vassil Peytchev wrote:

Since you want something like 00:05, I would suggest you use "G:i" as the formatting string. Note that it won't work for time differences larger than 24 hours.