PHP Find Days Between Two Date

<?php
  /*define a function.
  * @param1 $date2
  * @param2 $date2
  * return boolean (true/false)
  */
  function get_days($date1, $date2) 
  {
    $diff = strtotime($date2) - strtotime($date1);
    /*we knew that one day have 86400 seconds*/
    return abs(round($diff / 86400));
  }

  $date1 = "25-09-2021";
  $date2 = "31-01-2021";
  $days = get_days($date1, $date2);
  printf("Difference between two dates: ". $days . " Days ");
?>
				

Output

Difference between two dates: 237 Days