3v4l.org

run code in 300+ PHP versions simultaneously
<?php function prim($n) { if ( $n == 1 ) return false; if ( $n == 2) return true; if ( $n % 2 == 0 ) return true; for ( $i = 3; $i < ceil(sqrt($n)); $i+=2) { if ( $n % $i == 0 ) return true; } return false; } var_dump(prim(1)); var_dump(prim(2)); var_dump(prim(3)); var_dump(prim(4)); var_dump(prim(5)); var_dump(prim(6)); var_dump(prim(7)); var_dump(prim(8)); var_dump(prim(9)); var_dump(prim(11));
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 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
bool(false) bool(true) bool(false) bool(true) bool(false) bool(true) bool(false) bool(true) bool(false) bool(false)

preferences:
284.26 ms | 406 KiB | 456 Q