Getting last month's date in php

Question

I want to get last month\'s date. I wrote this out:

$prevmonth = date(\'M Y\');

Which gives me the current month/year. I can\'t tell if I

Answer 1

Incorrect answers are:

$lastMonth = date('M Y', strtotime("-1 month"));
$lastDate = date('Y-m', strtotime('last month'));

The reason is if current month is 30+ days but previous month is 29 and less $lastMonth will be the same as current month.

e.g.

If $currentMonth = '30/03/2016';
echo $lastMonth = date('m-Y', strtotime("-1 month")); => 03-2016
echo $lastDate = date('Y-m', strtotime('last month')); => 2016-03

The correct answer will be:

echo date("m-Y", strtotime("first day of previous month")); => 02-2016
echo sprintf("%02d",date("m")-1) . date("-Y"); => 02-2016
echo date("m-Y",mktime(0,0,0,date("m")-1,1,date("Y"))); => 02-2016