PHP code PHP singly linked list implementation code sharing

<&#63;php
/**
 * 单链表
 */ 
class Demo
{
  private $id;
  public $name;
  public $next;

  public function __construct ($id = '', $name = '')
  {
    $this->id = $id;
    $this->name = $name;
  }

  static public function show ($head)
  {
    $cur = $head;
    while ($cur->next) {
      echo $cur->next->id,'###',$cur->next->name,'<br />';
      $cur = $cur->next;
    }
    echo '<hr />';
  }

  //尾插法
  static public function push ($head, $node)
  {
    $cur = $head;
    while (NULL != $cur->next) {
      $cur = $cur->next;
    }
    $cur->next = $node;
    return $head;
  }

  static public function insert($head, $node)
  {
    $cur = $head;
    while (NULL != $cur->next) {
      if ($cur->next->id > $node->id) {
        break;
      }
      $cur = $cur->next;
    }
    $node->next = $cur->next;
    $cur->next = $node;
    return $head;
  }

  static public function edit($head, $node)
  {
    $cur = $head;
    while (NULL != $cur->next) {
      if ($cur->next->id == $node->id) {
        break;
      }
      $cur = $cur->next;
    }
    $cur->next->name = $node->name;
    return $head;    
  }

  static public function pop ($head, $node)
  {
    $cur = $head;
    while (NULL != $cur->next) {
      if ($cur->next == $node) {
        break;
      }
      $cur = $cur->next;
    }
    $cur->next = $node->next;
    return $head;      
  }
}

$team = new Demo();
$node1 = new Demo(1, '唐三藏');
Demo::push($team, $node1);
$node1->name = '唐僧';
Demo::show($team);

// Demo::show($team);
$node2 = new Demo(2, '孙悟空');
Demo::insert($team, $node2);
// Demo::show($team);
$node3 = new Demo(5, '白龙马');
Demo::push($team, $node3);
// Demo::show($team);
$node4 = new Demo(3, '猪八戒');
Demo::insert($team, $node4);
// Demo::show($team);
$node5 = new Demo(4, '沙和尚');
Demo::insert($team, $node5);
// Demo::show($team);
$node4->name = '猪悟能';//php对象传引用，所以Demo::edit没有必要
// unset($node4);
// $node4 = new Demo(3, '猪悟能');
// Demo::edit($team, $node4);
Demo::pop($team, $node1);

Demo::show($team);