PHP 实现单链表

header("Content-type:text/html;charset=utf-8");
//链表节点 
class node { 
    public static $count = -1; //节点id 
    public $name; //节点名称 
    public $next; //下一节点 
    public $id;

    public function __construct($name) { 
        $this->id = self::$count;
        $this->name = $name; 
        $this->next = null; 
        self::$count += 1;
    } 
}
//单链表 
class singelLinkList { 
    private $header;
    private $current;
    public $count;
   
    //构造方法 
    public function __construct($data = null) { 
        $this->header = new node ($data);
        $this->current = $this->header; 
        $this->count = 0;
    } 

    //添加节点数据 
    public function addLink($node) {
        if($this->current->next != null)
            $this->current = $this->current->next; 
        $this->count++;
        $node->next = $this->current->next; 
        $this->current->next = $node; 
    } 

    //删除链表节点 
    public function delLink($id) { 
        $current = $this->header; 
        $flag = false; 
        while ( $current->next != null ) { 
            if ($current->next->id == $id) { 
                $flag = true; 
                break; 
            } 
            $current = $current->next; 
        } 
        if ($flag) { 
            $this->count--;
            $current->next = $current->next->next; 
        } else { 
            echo "未找到id=" . $id . "的节点！
"; 
        } 
    }

    //获取链表 
    public function getLinkList() { 
        $this->checkNull();
        $current = $this->header; 
        while ( $current->next != null ) { 
            echo 'id:' . $current->next->id . '   name:' . $current->next->name . "
"; 
            if ($current->next->next == null) { 
                break; 
            } 
            $current = $current->next; 
        } 
    } 

        //获取长度
    public function getLinkLength()
    {
        echo $this->count;
    }

    //获取当前节点
    public function getCurrent()
    {
        $this->checkNull();
        echo '当前节点id:' . $this->current->next->id . '   name:' . $this->current->next->name . "
"; 
    }

    //判断是否为空
    public function checkNull()
    {
        if ($this->header->next == null) { 
            echo "链表为空!"; 
            exit;
        } 
    }

    //获取节点名字 
    public function getLinkById($id) { 
        $this->checkNull();
        $current = $this->header; 
        while ( $current->next != null ) { 
            if ($current->id == $id) { 
                break; 
            } 
            $current = $current->next; 
        } 
        echo '修改后id:' . $current->id . '   name:' . $current->name . "
"; 
    } 

    //更新节点名称 
    public function updateLink($id, $name) { 
        $this->checkNull();
        $current = $this->header; 
        while ( $current->next != null ) { 
            if ($current->id == $id) { 
                break; 
            } 
            $current = $current->next; 
        } 
        return $current->name = $name; 
    }
}
$list = new singelLinkList (); 
$list->addLink ( new node ('aaaaaa' ) ); 
$list->addLink ( new node ('bbbbbb' ) ); 
$list->addLink ( new node ('cccccc' ) ); 
$list->addLink ( new node ('dddddd' ) ); 
echo "所有链表节点：
";
$list->getLinkList(); 
echo "
";
echo "当前链表末位节点：
";
$list->getCurrent();
echo "
";
echo "修改链表节点id为0的：
";
$list->updateLink(0, '2222222');
echo "查找id为0的节点：
";
$list->getLinkById(0); 
echo "
";
echo "删除链表节点id为0：
";
$list->delLink(0); 
echo "所有链表节点：
";
$list->getLinkList(); 
echo "
";
echo "所有链表节点：
";
$list->getLinkLength (); 
?>