increment date by week

Hi

I am trying to increment the date using weekly increments.
I need to determine the start and end dates and the week number of the year.

If you can suggest another approache that is OK, but this is what I came up with.

I am having problems getting the correct increment and week number of the year.

result received:
(week number) 01-1
(next start) 1970-01-07
(next end) 1970-01-07

result expected:
(week number) 02
(next start) 2008-02-14
(next end) 2008-02-21

<?
$week number = 1;//the for loop increment number 
$week cycle = 2;//This will provide the date for the 1st, 2nd, 3rd or 4th week of the month.
$start_date = "2008-02-01";


$nw = ($week number * $week cycle) + 1;//+ 1 to be in the next range	

$next_start = date("Y-m-d",strtotime("+$nw week", $start_date));
$next_end = date('Y-m-d',strtotime("+1 week", $next_start))."<br>";
$week_number = date('W', $next_start);//week number of the year
?>

PHP:

 

um, just on first glance, but you have mixed labels for what I assume are the same variables:

$week number / $week cycle

AND

$week_number / $week_cycle

that needs fixing for starters if it isnt a typo - if it is, sorry and forget i spoke

 

The second argument of date() and strtotime() functions must be a unix timestamp.

<?
$week_number = 1;//the for loop increment number
$week_cycle = 2;//This will provide the date for the 1st, 2nd, 3rd or 4th week of the month.
$start_date = "2008-02-01";


$nw = ($week_number * $week_cycle) + 1;//+ 1 to be in the next range   

$next_start = date("Y-m-d",strtotime("+$nw week", strtotime($start_date)));
$next_end = date('Y-m-d',strtotime("+1 week", strtotime($next_start)))."<br>";
$week_number = date('W', strtotime($next_start));//week number of the year
?>

PHP:

 

Good solution thanks.