function move_special_characters_to_end($s) {
$len = strlen($s);
$chars = "";
$pecial_characters = "";
for ($i = 0; $i < $len; $i++) {
$ch = $s[$i];
if (ctype_alnum($ch)) {
$chars = $chars . $ch;
}
else {
$pecial_characters = $pecial_characters . $ch;
}
}
return $chars . $pecial_characters;
}
$s = "c++14@vb.net&%java*() php <>/python 3.7.3";
echo move_special_characters_to_end($s);
/*
run:
c14vbnetjavaphppython373++@.&%*() <>/ ..
*/