I don't know what's wrong with my code - Binary Tree - binary-tree

Question

I'm now making a Binary Tree in C++, using friend class.
But, something is wrong, and I cannot know what should I change
template <class Type>
class BinaryTree{
public:
BinaryTree(){
root = new BTNode<Type>();
currentNode = NULL;
}
~BinaryTree(){
delete root, currentNode;
};
void insertItem(Type data){
if(currentNode==NULL){
Item = data;
currentNode = root;
}
if(data<currentNode){
if(currentNode->Left.is_empty()){
currentNode->Left = new BTNode(data);
currentNode = root;
return;
}
else{
currentNode = currentNode->Left;
return insertItem(data);
}
}
if(data>currentNode){
if(currentNode->Right.is_empty()){
currentNode->Right = new BTNode(data);
currentNode = root;
return;
}
else{
currentNode = currentNode->Right;
return insertItem(data);
}
}
currentNode = root;
return;
}
void deleteItem(Type data){}
void is_empty(){
if (this == NULL) return 1;
else return 0;
}
void printInOrder(){
if(!(currentNode->Left).is_empty()){
currentNode = currentNode->Left;
}
}
private:
BTNode<Type>* currentNode;
BTNode<Type>* root;
};
and here the BTNode class that store the item of BinaryTree, and point the next Node:
template <class Type>
class BTNode{
public:
friend class BinaryTree<Type>;
BTNode(){}
BTNode(Type data){
Item = data;
}
~BTNode(){}
private:
Type Item;
BTNode<Type> *Left, *Right;
};
The Binary Tree class's BTNode*root point the first Node, and currentNode will point the 'current node' while doing something like insertion or merging the nodes.
But when I compile, the Compiler Error C2143 occurs in the BinaryTree class,
here:
BTNode<Type>* root;
BTNode<Type>* currentNode;
The error says that there is no toke ; in front of <
but I cannot know what is wrong

Answer 1

It appears as though BTNode isn't correctly defined inside the BinaryTree class. The compiler is not understanding that BTNode is a type. Make sure you're including and linking the files correctly.