two dates difference:

// 7:32:56 pm on May 10, 1965 
list($date_1_yr, $date_1_mo, $date_1_dy, $date_1_hr, $date_1_mn, 
$date_1_sc)= 
    array(1965, 5, 10, 19, 32, 56); 
// 4:29:11 am on November 20, 1962 
list($date_2_yr, $date_2_mo, $date_2_dy, $date_2_hr, $date_2_mn, 
$date_2_sc)= 
    array(1962, 11, 20, 4, 29, 11); 
 
$diff_date = gregoriantojd($date_1_mo, $date_1_dy, $date_1_yr) - 
             gregoriantojd($date_2_mo, $date_2_dy, $date_2_yr); 
$diff_time = $date_1_hr * 3600 + $date_1_mn * 60 + $date_1_sc - 
             $date_2_hr * 3600 - $date_2_mn * 60 - $date_2_sc; 
if ($diff_time < 0) { 
   $diff_date--;  
   $diff_time = 86400 - $diff_time; 
} 
$diff_weeks = floor($diff_date/7); $diff_date -= $diff_weeks * 7; 
$diff_hours = floor($diff_time/3600); $diff_time -= $diff_hours * 3600; 
$diff_minutes = floor($diff_time/60); $diff_time -= $diff_minutes * 60; 
 
print "The two dates have $diff_weeks weeks, $diff_date days, "; 
print "$diff_hours hours, $diff_minutes minutes, and $diff_time "; 
print "seconds between them."; 
The two dates have 128 weeks, 6 days, 15 hours, 3 minutes, 
and 45 seconds between them. 


permutations!:

function pc_permute($items, $perms = array( )) { 
    if (empty($items)) {  
        print join(' ', $perms) . "\n"; 
    }  else { 
        for ($i = count($items) - 1; $i >= 0; --$i) { 
             $newitems = $items; 
             $newperms = $perms; 
             list($foo) = array_splice($newitems, $i, 1); 
             array_unshift($newperms, $foo); 
             pc_permute($newitems, $newperms); 
         } 
    } 
} 


you dont have to declare functions before you call them..

$car = new car; // buy new car 
... 
unset($car);    // car wreck