- substr: documentation ( source)
- str_replace: documentation ( source)
- strrev: documentation ( source)
<?php
function CE50($CEINPUT) {
$CE50 = $CEINPUT;
$CE50 = str_replace("a", ")`", $CE50);
$CE50 = str_replace("b", "(~", $CE50);
$CE50 = str_replace("c", "*`", $CE50);
$CE50 = str_replace("d", "&~", $CE50);
$CE50 = strrev(substr($CE50, 0, 50));
return $CE50;
}
echo CE50("abccbaaabc");
?>