Question

I want to compute the next Xth day in the calendar.

For example today is 2012-10-08. if X=25 i want it to return 2012-10-25 but if X=06 i want 2012-11-06. If the month doesn’t have the required X days, it must return the last day of the month (if i’m looking for the 30th of february for example, it must return 28 or 29 if leap year)

It seems simple enough but I get caught by all the special cases (last month of the year, 28-31 day months, etc).

Answer 1

You can use strtotime() and t:

$x = 5;                   // given day
if(date('t') < $x){       // check if last day of the month is lower then given day
    $x = date('t');       // if yes, modify $x to last day of the month
}

$month = date('m');       // current month
if(date('d') >= $x){      // if $x day is now or has passed
    $month = $month+1;    // increase month by 1
}

$year = date('Y');        // current year
if($month > 12){          // if $month is greater than 12 as a result from previous if
    $year = date('Y')+1;  // increase year
    $month = 1;           // set month to January
}

if(date('t', strtotime($year.'-'.$month.'-01')) < $x){       // check if last day of the new month is lower then given day
    $x = date('t', strtotime($year.'-'.$month.'-01'));       // if yes, modify $x to last day of the new month
}

$date = date('d F Y', strtotime($year.'-'.$month.'-'.$x));
// 05 November 2012

HERE is a nice tutorial.