Having trouble returning class member - c++

Question

I'm making a B inary S earch T ree (BST for short) and I've run into a problem that I can't figure out.
I shall try and reduce the amount of code but it still may require quite a bit I'm afraid.
Nodes:
template <typename Type>
class BSTNode { // Binary Search Tree nodes
private:
int key; // we search by key, no matter what type of data we have
Type data;
BSTNode *left;
BSTNode *right;
public:
BSTNode (int, Type);
bool add (int, Type);
Type search (int);
BSTNode<Type> *remove (int, BSTNode*);
BSTNode<Type> *minNode (int);
};
Root:
template <typename Type>
class BST { // The binary search tree containing nodes
private:
BSTNode<Type> *root; // Has reference to root node
public:
BST ();
bool add (int, Type);
Type search (int);
bool remove (int);
};
I don't know how much code to give since I don't want to exaggerate, if you need more, say so please.
I do both do recursive search and remove
template<typename Type>
BSTNode<Type> *BSTNode<Type>::remove(int removeKey, BSTNode *parent) {
// Here I try to remove nodes
// Depending on the number of children a node has, I remove in different ways
// The error occurs at removing a node with 2 children
// here I look for smallest node greater than current node, replace current node, delete node I replaced WITH
if (this->left != NULL && this->right != NULL){
int *auxKey = &key;
this = this->right->minNode(auxKey); // replace
return this->right->remove(this->key, this); // remove old node
}
}
Here is minNode:
template<typename Type>
Type *BSTNode<Type>::minNode (int oldKey) {
if (this->left == NULL) {
//oldKey = this->key;
return this->data;
} else
return left->minNode();
}
This is where the error occurs:
this = right->minNode(auxKey);
This causes a chain of errors, but I think the main error is:
error: invalid conversion from 'int*' to 'int' [-fpermissive]
I'm guessing it's something simple I've overlooked, but I just can't find it, have been trying for quite some time.
EDIT: Decided for now to simply pass key to minNode() and ignore oldKey and auxKey, modified minNode to return pointer.
New Error, same place
lvalue required as left operand

Answer 1

Your minNode function takes in an int value representing the old key, but you're passing an int* into it in the remove function (specifically, auxKey). Try passing in the value of the old key, not a pointer to it. Alternatively, if you want to update the in parameter to hold the correct value (you seem to be trying to do this), change the parameter to a reference parameter.
Hope this helps!