3v4l.org

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<?php $initialDate = "2011-07-31"; for($i=1; $i<=5; $i++) { echo date('Y-m-d', strtotime('last day of -' . $i . ' month', strtotime($initialDate))) . "\n"; }
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.13
2011-06-30 2011-05-31 2011-04-30 2011-03-31 2011-02-28

preferences:
146.78 ms | 408 KiB | 5 Q