I am receiving the following compile errors:

BinarySearchTree.cpp:3: error: expected constructor, destructor, or type conversion before â<â token
BinarySearchTree.cpp:9: error: expected initializer before â<â token
BinarySearchTree.cpp:15: error: expected initializer before â<â token
BinarySearchTree.cpp:21: error: expected initializer before â<â token

Looking at my implementation, I fail to see the errors. I wonder if overloading the methods is the problem or not. Here is the rest of my code:

#ifndef BINARY_SEARCH_TREE_H
#define BINARY_SEARCH_TREE_H
#include <cstdlib>
#include <functional>

template <class T, class Key = T, class Compare = std::less<Key> >
class BinarySearchTree
{
	private:
		struct BinaryNode
		{
			T data;
			Key key;
			BinaryNode *left;
			BinaryNode *right;
			BinaryNode() : {left = NULL; right = NULL;}
			BinaryNode(Key k, T i) : data(i), key(k) {left = NULL; right = NULL;}
			~BinaryNode() : {delete left; delete right;}

		};
		BinaryNode *root;
		
		Compare compare;
	
	public:
		BinarySearchTree();
		void InsertSorted(const T& data);
		void InsertSorted(const Key& key, const T& data);
	
	private:
		void InsertSortedR(const Key& key, const T& data, BinaryNode*& node);
};

#include "BinarySearchTree.cpp"

#endif
template <class T, class Key, class Compare>
BinarySearchTree<T, Key, Compare>::BinarySearchTree() 
{
	root = NULL;
}

template <class T, class Key, class Compare>
void BinarySearchTree<T, Key, Compare>::InsertSorted(const T& item)
{
	InsertSorted(item, item);
}

template <class T, class Key, class Compare>
void BinarySearchTree<T, Key, Compare>::InsertSorted(const Key& key, const T& item)
{
	InsertSortedR(key, item, root);
}

template <class T, class Key, class Compare>
void BinarySearchTree<T, Key, Compare>::InsertSortedR(const Key& key, const T& item, BinaryNode*& node)
{
	// Base case: Reached end of list, or found sorted position
	if (node == NULL || compare(key, node->key))
	{
		// Create new list node
		BinaryNode *new_node = new BinaryNode(key, item);
		//new_node->next = node;
		
		// Update linked list
		node = new_node;
		
		if (root == NULL) // if list was empty, update tail
		{
			root = new_node;
		}
	}
	// Recursive case:
	else
	{
		InsertSortedR(key, item, node->right);
	}
}

If anyone could please help me with this error it would be greatly appreciated. Thanks in advance.

You can put the BinaryNode struct outside of the class and make the class look a little more cleaner.

Why are you including the .cpp file, it's not a header?

Shouldn't the destructor test if the pointers are NULL first?

First off I am going to deal with the minor errors. The the major problem.

Number of minor errors:

(A) Only constructors take the ":" assignment . Error in line 18 in
destructor. It should read ~BinaryNode() {delete left; delete right;} (B) Maybe delete line Compare compare . Use it as a direct functor if (node == NULL || Compare()(key, node->key)) Major:

This code is unlikely to behave as expected. If you put say in keys
3,5,1 then when it inserts a new node, it does no re-attach the
existing items to the tree. (as well as not working, this is a memory leak)

Additionally, I feel that you are being let down by your compiler. It is not reporting useful error messages. It really helps to have another compiler sometime (e.g. gcc) [likewise if you use gcc most of the time, something like Portland or IBM etc].

Finally, it is strange to include the .cpp file in the .h file. That is because you want to use the header without including all the code. If you need a template instance, then sometimes it needs to be done
but not all the time.

I look forward to the next installment :)

So the problem was part (A). Removed the colons and the code works. It might not be perfect, but it is functional. I included the cpp in the h file due to laziness. I used this class previously so there was not much to change. I've tried using Microsoft based compilers, but they have issues compiling my code where gcc finds no faults. I need to look into other compilers. Thanks for the help everyone!

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