3v4l.org

run code in 300+ PHP versions simultaneously
<?php $items=array("a","b","c","d"); for ($i=0;$i<4;$i++) { $item=&$items[$i]; $item=$item.$item; } print_r($items); foreach ($items as $item) echo $item."\n"; print_r($items);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
Array ( [0] => aa [1] => bb [2] => cc [3] => dd ) aa bb cc cc Array ( [0] => aa [1] => bb [2] => cc [3] => cc )
preferences:
307.81 ms | 406 KiB | 461 Q