//链表节点 
class node { 
    public $id; //节点id 
    public $name; //节点名称 
    public $next; //下一节点 
    
public function __construct($id, $name) { 
        $this->id = $id; 
        $this->name = $name; 
        $this->next = null; 
    } 
}
//单链表 
class singelLinkList { 
    private $header; //链表头节点 
    
//构造方法 
    public function __construct($id = null, $name = null) { 
        $this->header = new node ( $id, $name, null ); 
    } 
    //获取链表长度 
    public function getLinkLength() { 
        $i = 0; 
        $current = $this->header; 
        while ( $current->next != null ) { 
            $i ++; 
            $current = $current->next; 
        } 
        return $i; 
    } 
    //添加节点数据 
    public function addLink($node) { 
        $current = $this->header; 
        while ( $current->next != null ) { 
            if ($current->next->id > $node->id) { 
                break; 
            } 
            $current = $current->next; 
        } 
        $node->next = $current->next; 
        $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) { 
            $current->next = $current->next->next; 
        } else { 
            echo "未找到id=" . $id . "的节点!<br>"; 
        } 
    } 
    //获取链表 
    public function getLinkList() { 
        $current = $this->header; 
        if ($current->next == null) { 
            echo ("链表为空!"); 
            return; 
        } 
        while ( $current->next != null ) { 
            echo 'id:' . $current->next->id . '   name:' . $current->next->name . "<br>"; 
            if ($current->next->next == null) { 
                break; 
            } 
            $current = $current->next; 
        } 
    } 
    //获取节点名字 
    public function getLinkNameById($id) { 
        $current = $this->header; 
        if ($current->next == null) { 
            echo "链表为空!"; 
            return; 
        } 
        while ( $current->next != null ) { 
            if ($current->id == $id) { 
                break; 
            } 
            $current = $current->next; 
        } 
        return $current->name; 
    } 
    //更新节点名称 
    public function updateLink($id, $name) { 
        $current = $this->header; 
        if ($current->next == null) { 
            echo "链表为空!"; 
            return; 
        } 
        while ( $current->next != null ) { 
            if ($current->id == $id) { 
                break; 
            } 
            $current = $current->next; 
        } 
        return $current->name = $name; 
    } 
}
