3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str = "racecar"; $pal = ""; for($a=0; $a<strlen($str); $a++) { for($z=0; $z<strlen($str); $z++) { $subs = substr($str, $a, $z); if( $subs == strrev($subs) and strlen($subs) > strlen($pal) ) { $pal = $subs; } } } echo $pal;
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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
aceca
preferences:
258.6 ms | 406 KiB | 457 Q