Online PHP editor | refs for QBQUB

<?php function display(\DateTimeInterface $start, \DateTimeInterface $end) { echo $start->format('Y-m-d H:i T') . ' to ' . $end->format('Y-m-d H:i T') . \PHP_EOL; $periods = new \DatePeriod($start, new \DateInterval('PT1H'), $end); $hours = iterator_count($periods); echo $hours . ' hours (iterator_count)'; echo \PHP_EOL; $diff = $end->getTimestamp() - $start->getTimestamp(); $hours = $diff / ( 60 * 60 ); echo $hours . ' hours (60 * 60)'; echo \PHP_EOL; $diff = $end->diff($start); $hours = $diff->h + ($diff->days * 24); echo $hours . ' hours (days * 24)'; } function go(\DateTimezone $tz) { date_default_timezone_set($tz->getName()); //DST starts Apr. 2nd 02:00 and moves to 03:00 display( new \DateTime('2006-04-01T12:00:00'), new \DateTime('2006-04-02T12:00:00') ); echo \PHP_EOL . \PHP_EOL; //DST ends Oct. 29th 02:00 and moves to 01:00 display( new \DateTime('2006-10-28T12:00:00'), new \DateTime('2006-10-29T12:00:00') ); echo \PHP_EOL . \PHP_EOL; //full year display( new \DateTime('2006-01-01T12:00:00'), new \DateTime('2007-01-01T12:00:00') ); } go(new \DateTimezone('America/New_York')); echo \PHP_EOL . \PHP_EOL . '---------' . \PHP_EOL . \PHP_EOL; go(new \DateTimezone('UTC'));