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<?php function reverseString($string) { $l = strlen($string)-1; for($i=0; $i<$l/2; $i++) { $string[$i] = $string[$i] ^ $string[$l-$i]; $string[$l-$i] = $string[$i] ^ $string[$l-$i]; $string[$i] = $string[$i] ^ $string[$l-$i]; } return $string; } var_dump(reverseString('foob'));

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