3v4l.org

run code in 300+ PHP versions simultaneously
<?php function fib($n) { if ($n < 0) { return NULL; } elseif ($n === 0) { return 0; } elseif ($n === 1 || $n === 2) { return 1; } else { return fib($n-1) + fib($n-2); } } echo fib(12);
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 - 5.5.37, 5.6.0 - 5.6.23, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.29 - 7.2.33, 7.3.12 - 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 - 8.3.6
144
preferences:
266.53 ms | 406 KiB | 347 Q