3v4l.org

run code in 300+ PHP versions simultaneously
<?php $foo = [10, 20, 30]; echo $foo[]++; echo "\n---\n"; var_export($foo); echo "\n---\n"; echo ++$foo[], "\n", --$foo[], "\n"; var_export($foo); echo "\n===\n"; var_export(--$foo[]);
Output for 8.3.0 - 8.3.4
--- array ( 0 => 10, 1 => 20, 2 => 30, 3 => 1, ) --- 1 Warning: Decrement on type null has no effect, this will change in the next major version of PHP in /in/CjFPn on line 8 array ( 0 => 10, 1 => 20, 2 => 30, 3 => 1, 4 => 1, 5 => NULL, ) === Warning: Decrement on type null has no effect, this will change in the next major version of PHP in /in/CjFPn on line 11 NULL
Output for 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 - 8.1.27, 8.2.0 - 8.2.17
--- array ( 0 => 10, 1 => 20, 2 => 30, 3 => 1, ) --- 1 array ( 0 => 10, 1 => 20, 2 => 30, 3 => 1, 4 => 1, 5 => NULL, ) === NULL

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