Templates "no matching function for call to"

[rtzoeller]

When I try to create an opject of type rbtree it appears to complete the initialization successfully, however, when I try to insert a node using the public member insert, it return this while compiling:

error: no matching function for call to ‘rbtree<std::basic_string<char>>::insert(std::basic_string<char>&, node<std::basic_string<char> >*&)’

template <typename T>
struct node
{
    T data;
    bool red;
    node<T> *link[2]; // [0] is left, [1] is right

};

template <typename T>
class rbtree
{
public:
    rbtree() // Construct without arguments; nodes are inserted later
    {
        treeRoot=NULL;
    };

    void insert (T data) // Insert a new node and balance the tree
    {
        if(treeRoot!=NULL)
        {
            insert(data, treeRoot); // Call a recursive insert to find the right place
        }
        else
        {
            treeRoot=new node<T>;
            treeRoot->data=data;
            treeRoot->link[0]=NULL;
            treeRoot->link[1]=NULL;
        }
    };
    node<T> *search (T data) // Search the tree for a node
    {

    };
    void print (); // Print inorder traversal of tree to stdout
private:
    node<T> *treeRoot; // Root node of tree
    bool isRed (node<T> *root) // Helper function to determine if a node is red or not (assume null pointers are black)
    {
        return root != NULL && root->red == true;
    };
    void insert (T data, node<T> root)
    {
        if(data< root->data)
        {
            if(root->link[0]!=NULL)
                insert(data, root->link[0]);
            else
            {
                root->link[0]=new node<T>;
                root->link[0]->data=data;
                root->link[0]->link[0]=NULL;    //Sets the left child of the child node to null
                root->link[0]->link[1]=NULL;   //Sets the right child of the child node to null
            }
        }
        else if(data>=root->data)
        {
            if(root->link[1]!=NULL)
                insert(data, root->link[1]);
            else
            {
                root->link[1]=new node<T>;
                root->link[1]->data=data;
                root->link[1]->link[0]=NULL;  //Sets the left child of the child node to null
                root->link[1]->link[1]=NULL; //Sets the right child of the child node to null
            }
        }
    };
    node<T> *singleRotate (node<T> *root, bool dir); // Rotate once. False is left, true is right.

};

Any ideas? It seems like it should be compiling okay, and I don't see how it could be an ambiguous case.

[webJose]

Your private overload for insert() takes the node by value and T by value, while the error message says you are passing T by reference and a pointer to a node by reference, and this is the overload that it complains it cannot find.

[rtzoeller]

What changes would you recommend to fix that?

[webJose]

First of all, your insert() function should take T and node<T> by reference to increase performance and avoid copy construction, which may be problematic on more complex data types (classes).

Second: Your treeRoot variable is of type "pointer to a node<T>", but your insert takes a node<T>. If you want to preserve treeRoot's data type (I would), then you need to change your insert() overload to take a pointer of node<T>, or call the overload in line 23 as insert(data, *treeRoot);. If you change your overload to accept a pointer, then take the pointer by value; if you leave your overload as you have it now, then at least take the node by reference.

[rtzoeller]

Thanks, that seemed to fix it.