Implementation of PHP data structure single linked list

Learn PHP, learn the grammar, start to try to implement the data structure, the realization of the single-linked list today

<?php class Node//node data structure {public $id;        Public $name;        Public $next;            Public function __construct ($id, $name)//constructor {$this->id= $id;            $this->name= $name;        $this->next=null;        }} class Linklist//linked list data structure {private $header;        Public function __construct ()//list constructor {$this->header=new node ($id =null, $name =null);            The Public function Add ($node)//function {$current = $this->header; To add a node to the list                while ($current->next!=null) {if ($current->id> $node->id) break;                else if ($current->next== $node->id) {exit (' already exist! ');            } $current = $current->next;            } $node->next= $current->next;        $current->next= $node;    } Public Function del ($id)Deleting a node in a linked list {$current = $this->header;            $flag =false;                    while ($current->next!=null) {if ($current->next->id== $id) {                    $flag =true;                Break            } $current = $current->next;            if ($flag) $current->next= $current->next->next;        else echo "Can not find the node which id=". $id;            } public Function GetLength ()//Gets the length of the linked list {$current = $this->header;            $i = 0;                while ($current->next!=null) {$i + +;            $current = $current->next;        } return $i;            } public Function GetList ()//Gets the entire list {$current = $this->header;  if ($current->next==null) {echo "Empty list";            Empty table return;         }   while ($current->next!=null) {echo "id=". $current->next->id. ",". " Name= ". $current->next->name."                <br> ";                if ($current->next->next==null) break;            $current = $current->next;            }} Public Function Update ($id, $name)//Update table {$current = $this->header;            if ($current->next==null) exit ("Empty list");                while ($current->next!=null) {if ($current->id== $id) break;            $current = $current->next;        } return $current->name= $name;   }} $list =new linklist ();    Constructs a table $list->add (new node (1, ' AAA '));    $list->add (New node (2, ' BBB '));    $list->add (New node (3, ' CCC '));    $list->add (New node (4, ' ddd '));    $list->add (New node (5, ' Eee '));    $list->add (new node (6, ' FFF '));    $list->add (new node (7, ' GGG ')); $liSt->add (new node (8, ' hhh '));    $list->add (new node (9, ' III '));    $list->getlist (); echo "<br/> the length is". $list->getlength (). "    <br/> ";    echo "Test delete node <br/>";    $list->del (' 8 ');    $list->getlist ();    echo "Test update node <br/>";    $list->update (' 9 ', ' AAA '); $list->getlist ();? >

　　

The output is:
　　　

           Id=1, Name=aaa  id=2, name=bbb  id=3, NAME=CCC  id=4, name=ddd  id=5, name=eee  id=6, Name=fff  id=7, name=ggg  id=8, name=hhh  id=9, name=iii the  length is 9     test Delete node I  D=1, Name=aaa id=2, name=bbb          id=3, NAME=CCC id=4, name=ddd id=5, name=eee id=6, Name=fff id=7  , Name=ggg id=9, NAME=III Test update node id=1, name=aaa id=2, name=bbb id=3, NAME=CCC id=4, name=ddd id=5 , Name=eee id=6, Name=fff id=7, Name=ggg id=9, NAME=AAA