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run code in 150+ php & hhvm versions
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<?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); } } fib(12);
Output for 4.3.0 - 7.1.0