3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = array(1 => 2, 6=>7, 3=>4); foreach($a as &$key => $value){ $key *= 10; } print_r($a);
Output for 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 - 5.4.32
Fatal error: Key element cannot be a reference in /in/IENGp on line 4
Process exited with code 255.
Output for 4.4.2 - 4.4.9
Parse error: syntax error, unexpected '&', expecting T_VARIABLE or '$' in /in/IENGp on line 4
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1
Parse error: parse error, unexpected '&', expecting T_VARIABLE or '$' in /in/IENGp on line 4
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error, expecting `T_VARIABLE' or `'$'' in /in/IENGp on line 4
Process exited with code 255.
preferences:
204.26 ms | 1399 KiB | 123 Q