Online PHP editor | output for 9Jjp7

@ 2013-12-24T15:00:25Z

<?php
function weeks_in_month($month, $year)
{
    $startDate = new DateTime();
    $startDate->setDate($year, $month, 1);

    $loopDate = $startDate;
    $week = 1;
    for($i = $startDate->format('d'); $i <= cal_days_in_month(CAL_GREGORIAN, $month, $year); $i++)
    {
        if($loopDate->format('w') % 7 == 0)
        {
            $week++;
        }

        $loopDate->modify('+1 day');
    }

    return $week;
}

echo '<p>Jan '.weeks_in_month(1, 2014).'</p>';
echo '<p>Feb '.weeks_in_month(2, 2014).'</p>';
echo '<p>Mar '.weeks_in_month(3, 2014).'</p>';
echo '<p>Apr '.weeks_in_month(4, 2014).'</p>';
echo '<p>May '.weeks_in_month(5, 2014).'</p>';
echo '<p>Jun '.weeks_in_month(6, 2014).'</p>';
echo '<p>Jul '.weeks_in_month(7, 2014).'</p>';
echo '<p>Aug '.weeks_in_month(8, 2014).'</p>';
echo '<p>Sep '.weeks_in_month(9, 2014).'</p>';
echo '<p>Oct '.weeks_in_month(10, 2014).'</p>';
echo '<p>Nov '.weeks_in_month(11, 2014).'</p>';
echo '<p>Dec '.weeks_in_month(12, 2014).'</p>';

Output for 7.1.20, 7.2.6 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: Fatal error: Uncaught Error: Call to undefined function cal_days_in_month() in /in/9Jjp7:9 Stack trace: #0 /in/9Jjp7(22): weeks_in_month(1, 2014) #1 {main} thrown in /in/9Jjp7 on line 9
Process exited with code 255.
Output for 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0: Jan 5Feb 5Mar 6Apr 5May 5Jun 6Jul 5Aug 6Sep 5Oct 5Nov 6Dec 5
Output for 5.0.0 - 5.0.5, 5.1.0 - 5.1.6: Fatal error: Class 'DateTime' not found in /in/9Jjp7 on line 4
Process exited with code 255.
Output for 4.3.2 - 4.3.11, 4.4.0 - 4.4.9: Fatal error: Cannot instantiate non-existent class: datetime in /in/9Jjp7 on line 4
Process exited with code 255.
Output for 4.3.0 - 4.3.1: Fatal error: Cannot instantiate non-existent class: datetime in /in/9Jjp7 on line 4

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