3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php for( $K = 'Key', $_ = range($i = $j = 0, $n = 255); $i <= $n; $j += $_[$i] + ord($K{$i % strlen($K)}), _($_[ $j &= $n ], $_[ $i++ ]) ); for($j = 0, $i = 1;; $j += $_[ $i &= $n ], _($_[ $j &= $n ], $_[$i]), printf('%x', $_[ ( $_[ $i++ ] + $_[$j] ) & $n ]) ); function _(&$i, &$j){ $x = $i; $i = $j; $j = $x; }
Output for 5.4.0 - 5.6.2
Fatal error: Cannot redeclare _() in /in/WfJLj on line 36
Process exited with code 255.