成员引用基类型'Node <int>*'不是结构或联合

Question

我正在尝试创建二叉树结构.我有一个Node类,以及一个操纵节点的Tree类.我编译时得到这个错误,我无法弄清楚什么是错的.

这是我的节点类..

template < typename NODETYPE >
class Node
{
    friend class Tree<NODETYPE>;
    friend class Queue<NODETYPE>;
private:
    NODETYPE m_Data;
    Node<NODETYPE> *m_pLeft;
    Node<NODETYPE> *m_pRight;
    Node<NODETYPE> *m_pNext;

public:
    //-------------------------------------
    //-- Constructor                      -
    //-------------------------------------
    Node( const NODETYPE &node_data )
        :m_Data( node_data ),
         m_pLeft( 0 ),
         m_pRight( 0 ),
         m_pNext( 0 )
        {
        };

    //-------------------------------------
    //-- Get Node Data                    -
    //-------------------------------------
    NODETYPE get_data() const { return m_Data; };
};

我的树类..

template < typename NODETYPE >
class Tree
{
private:
    Node<NODETYPE> *m_pRoot;

    //--------------------------------------
    //-- Utility Functions                 -
    //--------------------------------------
    void insert_helper( Node<NODETYPE> **pNode, const NODETYPE &node_data );

public:
    //--------------------------------------
    //-- Constructor / Destructor          -
    //--------------------------------------
    Tree()
        :m_pRoot( 0 ) {};
    ~Tree();

    //--------------------------------------
    //-- Public Member Functions           -
    //--------------------------------------
    void insert_new_node( const NODETYPE &node_data );
    void levelOrder_traversal() const;
};

我在成员函数'insert_new_node()'中得到错误.这是实施..

//------------------------------------------
//-- Insert New Node In Tree               -
//------------------------------------------
template < typename NODETYPE >
void Tree<NODETYPE>::insert_new_node( const NODETYPE &node_data )
{
    insert_helper( &m_pRoot, node_data );
}



//------------------------------------------
//-- Insert New Node Helper                -
//------------------------------------------
template < typename NODETYPE >
void Tree<NODETYPE>::insert_helper( Node<NODETYPE> **pNode, const NODETYPE &node_data )
{
    if( *pNode == 0 )
    {
        *pNode = new Node<NODETYPE>( node_data );
    }
    else
    {
        if( node_data < ( *pNode->get_data() ) ) <---- LINE THAT THROWS ERROR
        {
            insert_helper( &(*pNode -> m_pLeft), node_data );
        }
        else if( node_data > *pNode -> get_data() )
        {
            insert_helper( &(*pNode -> m_pRight), node_data );
        }
        else
        {
           std::cout << "Node Value '" << node_data << "' is a duplicate"
                     << std::endl;
        }
    }
}

错误复制:

In file included from /home/ellipsis/c++_projects/school_projects/advanced_c++/final_exam/20.24/main.cpp:14:
/home/ellipsis/c++_projects/school_projects/advanced_c++/final_exam/20.24/TreeLib/Tree.cpp:84:34: error: member reference base type
    'Node<double> *' is not a structure or union
    if( node_data < ( **pNode->get_data() ) )
                        ~~~~~^ ~~~~~~~~

我在这里查看了其他答案,与此错误相关,但我还没有发现任何有用的东西.

任何帮助将不胜感激.谢谢

Answer 1

这->是在发生之前发生的*,所以编译器试图使用 - > get_data,Node<NODETYPE> **它不起作用.

代替

*pNode->get_data()

使用

(*pNode)->get_data()