在再简化代码需求～该如何解决

$x = md5($row['userid']."+".$row['pwd']);
$str = base64_encode($row['userid'].".".$x);
//print_r($str);die;
$b=explode("/",DEDEROOT);
$c=$b['1'];
$a ='/reg/resetpw.php?p='.$str;
$a = "$c.$a"; 

list($b,$c,$d)=explode("/",DEDEROOT);
$a ='/reg/resetpw.php?p='.base64_encode($row['userid'].".".md5($row['userid']."+".$row['pwd']));
$a = "$c.$a";

strtok(DEDEROOT, "/");
$a ='/reg/resetpw.php?p=' . base64_encode($row['userid'].".".md5($row['userid']."+".$row['pwd']));
$a = "".strtok("/")."$a";