Irregular behavior counting between two dates

[wayang_mbeling]

hey guys...

i have found irregular behavior in my function (a modified version from existing function that i found in this forum). The function should calculate n display dates of every other fridays between two dates. The function works fine from month of January 2003 through September 2003. However, it suddenly miscalculate the dates at the end of October.

<?
function fof_dates($startdate,$enddate){
$startdate = strtotime($startdate);
$enddate = strtotime($enddate);
$i = $startdate;

  while($i <= $enddate) {
    $dates = $dates."    ".date("Y-m-d",$i);
 	$i = $i + (86400*14);
  }

$fof_ardates = explode("    ",$dates);

for($s=0; $s<=count($fof_ardates); $s++)
{
	print "$fof_ardates[$s] <br>";
}

return $fof_ardates;

}
?>

<? 
$sdate = "2003/09/19";
$edate = "2004/01/16";
$info = "FOF";
$foflistdates = fof_dates($sdate, $edate);

print "<p>&nbsp;&nbsp;</p>";

$sdate = "2003/05/02";
$edate = "2003/09/05";
$info = "FOF";
$foflistdates = fof_dates($sdate, $edate);

?>

here is the result it generates:

.
2003-05-02
2003-05-16
2003-05-30
2003-06-13
2003-06-27
2003-07-11
2003-07-25
2003-08-08
2003-08-22
2003-09-05

2003-09-19
2003-10-03
2003-10-17
2003-10-30
2003-11-13
2003-11-27
2003-12-11
2003-12-25
2004-01-08
.

as you can see...from 2003-05-02 to 2003-09-05, the dates are correct. But, from 2003-09-19 to 2004-01-16, it prints 2003-10-30 instead of 2003-10-31. it misses by 1 day. that causes miscalculation to the rest of the calculation.

Can some of you give me a little explanation about this problem? a solution for it will be greatly appreciated ... javascript:smilie('😉')

Thanks in advance...

[Jeb_]

Well, I know this is no help, but that code works fine on my machine.

So that leads me to one conclusion - it's a locale or timezone problem on the server. You could try creating a GMT date and adding the appropriate offset, that may or may not make a difference.

[EDIT]
Another thought occurred to me - daylight savings time, possibly?
[/EDIT]

[tekky]

nice to see stuff I helped with being used for other things... however thats not a very direct way of doing it 🙂

here's some really short code that prints every other friday between 2 dates

<? 
$start_day = strtotime("03 Jan 2003"); //test start day 
$end_day = strtotime("22 May 2004"); //test stop day 
if (date("w", $start_day) != 5) //is this first day a friday? 
	$start_day = strtotime("last friday", $start_day); //no.. so we'll get the previous friday using strtotimes relative time functions 
for($this_day = $start_day; $this_day<$end_day;$this_day = strtotime("1 fortnight", $this_day )) //loop while $this_day is less than or equal to $end_day (or equal to incase the last day is also a friday) 
{ 
	echo date("D, m-d-Y", $this_day). "<br>"; //echo "day of week" + mm-dd-yyyy 
	$date_arr[] = date("m-d-Y", $this_day); //build your array 
} //all done! 
echo '<pre>'.print_r($date_arr).'</pre>'; //visual output of the array for trouble shooting 
?> 

last edit I swear

[planetsim]

Theres heaps of ways doing this..

strotime, mktime, date using database.

But basically you will need to convert the date/time into a unix timestamp.

Than you can use date or gmdate to make them into readable dates.

[wayang_mbeling]

hey guys...thanks for the replies...sorry for late respond from me...

i havent had a chance to play around with Jeb's and planetsim's suggestions yet...

but, i tried tekky's code though and it looks like it works fine. i'll try to implement it to my application soon.

i'll give u guys the result later...

Thanks once again...

[wayang_mbeling]

Hey all...just tried tekky's code in my application...and it works like a charm...THANKS A LOT tekky...
javascript:smilie('😃')

however, tekky, can you give me some explanation why my... oooppss... i should say ur old function code does not work properly for this task?

Thanks again for you guys whom tried to help...i love this forum...