没有匹配的构造函数，无法初始化模板化类的构造函数

Question

I'm trying to create a template based tree where the nodes are specialized such that the methods accessing the element of the node and the child nodes return the child node type. Below is the abridged version of the code.

template<class NodeObjectType, class ChildNodeObjectType, class ChildNode>
class Node {
public:
    Node(Node* parent, NodeObjectType* object);
    ChildNode* addAsChild(ChildNodeObjectType* object);
private:
    NodeObjectType* nodeObject;
    std::vector<ChildNode*> children;
};

typedef Node<B, void, void> BNode;
typedef Node<A, B, BNode> ANode;
typedef Node<void, A, ANode> RootNode;

/* constructor */

template<class NodeObjectType, class ChildNodeObjectType, class ChildNode>
ChildNode* Node<NodeObjectType, ChildNodeObjectType, ChildNode>::
  addAsChild(ChildNodeObjectType* object)
{
    ChildNode* child = new ChildNode(this, object);
    children.push_back(child);
    return child;
}

The error is in the new ChildNode() call in addAsChild. Am I trying to do something that can't be done, or have I just made some mistake somewhere?

Answer 1

In Node(Node* parent, NodeObjectType* object);

Node is in reality Node<NodeObjectType, ChildNodeObjectType, ChildNode>> .

So for ANode : ANode(ANode* parent, A*);

So when you do something like:

A a;
RootNode root(nullptr, nullptr);
ANode anode(nullptr, &a);
root.addAsChild(&a);

you will call ChildNode* child = new ChildNode(this, object); or with some replacement:

ANode child = new ANode(root, &a);
// error: no matching function for call to
// 'Node<A, B, Node<B, void, void> >::Node(Node<void, A, Node<A, B, Node<B, void, void> > >* const, A*&)'

As RootNode is a different type as ANode (template parameters differ), there is a compilation error.

Maybe you want some BaseNode as parent node instead.