Online PHP editor | output for nGH6a

<?php $daysInMonth = array(0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); $timestampFailing = false; for ($year = 1500; $year < 2000; $year++) { for ($month = 1; $month <= 12; $month++) { for ($day = 1; $day < $daysInMonth[$month]; $day++) { $baseString = sprintf("%4d-%02d-%02d 00:00:00", $year, $month, $day); $timestamp = strtotime($baseString); if (!$timestamp) { $timestampFailing = true; echo "Timestamp failing start at $baseString\n"; continue; } if ($timestampFailing && $timestamp) { $timestampFailing = false; echo "Timestamp failinng end at $baseString\n"; } $roundTrip = date("Y-m-d H:i:s", $timestamp); if ($baseString !== $roundTrip) { echo "$baseString ($timestamp) $roundTrip\n"; } } } }