Bagaimana Menghitung Jumlah dan Selisih Dua Waktu yang Berbeda Menggunakan PHP

<?php
 
/**
 * @author Masino Sinaga, http://www.openscriptsolution.com
 * @copyright August 23, 2010
 */
 
$time1 = '12:12:20';
$time2 = '13:14:29';
echo 'Begin of Time: '.$time1;
echo '<br />End of Time: '.$time2;
echo '<br />The Sum of Time: '. sum_the_time($time1, $time2);  // this will give you a result: 19:12:25
echo '<br />Duration: '. duration_time($time1, $time2); // this will give you a result: 0 Day(s), 1 Hour(s), 2 Minute(s), 9 Second(s).
 
function sum_the_time($time1, $time2) {
  $times = array($time1, $time2);
  $seconds = 0;
  foreach ($times as $time)
  {
    list($hour,$minute,$second) = explode(':', $time);
    $seconds += $hour*3600;
    $seconds += $minute*60;
    $seconds += $second;
  }
  $hours = floor($seconds/3600);
  $seconds -= $hours*3600;
  $minutes  = floor($seconds/60);
  $seconds -= $minutes*60;
  // return "{$hours}:{$minutes}:{$seconds}";
  return sprintf('%02d:%02d:%02d', $hours, $minutes, $seconds);
}
 
function duration_time($parambegindate, $paramenddate) {
  $begindate = strtotime($parambegindate);
  $enddate = strtotime($paramenddate);
  $diff = intval($enddate) - intval($begindate);                 
  $diffday = intval(floor($diff/86400));
  $modday = ($diff%86400);
  $diffhour = intval(floor($modday/3600));
  $diffminute = intval(floor(($modday%3600)/60));
  $diffsecond = ($modday%60);
  return round($diffday)." Day(s), ".round($diffhour)." Hour(s), ".round($diffminute,0)." Minute(s), ".round($diffsecond,0)." Second(s).";
}
 
?>