looping

[Anon]

I need some help to format a loop... I have a system where all months are splitted into 2 periods, period 1 starts at the 1st., and period 2 starts at the 16th.

I have a start date and a end date and now I want to find all periods between the 2 dates.
Periods date must be rounded down down to 01 or 16.

Example:

$start_day = "2001-11-18"; // period 2001-11-16
$end_day = "2002-03-07"; // period 2002-03-01

I need the loop to echo all periods between the two dates, starting with:
2001-11-16
2001-12-01
2001-12-16
2002-01-01
.....etc ->
2002-03-01

I have played a little with mktime but I can't really think of the format of the loop. Any help would be great.

Thanks,
Michael

[Anon]

i am an adept of the explode function..
a simple way would be:

$start_day = "2001-11-18"; // period 2001-11-16

$start = explode('-', $start_day);
if ((integer)$start[2]<16) echo 'period '.$start[0].'-'.$start[1].'-01';
else echo 'period '.$start[0].'-'.$start[1].'-16';

you can do better tests, like count($start)=3,$start[2]>0, <32...
its hard to suggest a good loop format because i dont know from where you get that strings..