php date format YYYY-MM-DD minus or add one week from now?

Question

today 22-05-2011 so it should be 29-05-2011? ( plus 1 week ) 
or
today 22-05-2011 so it should be 15-05-2011? ( minus 1 week ) 

thanks for looking

Answer 1

You can use the DateTime class to do calendar calculations. For exaple, to add one week, you could use code like this:

$date = new DateTime('22-05-2011');
$date->modify('+1 week');