Binary search tree error LNK2019

[lauren1]

I'm making a template binary search tree class and I'm having the following error:

error LNK2019: unresolved external symbol "public: void __thiscall Tree<int>::insert(int)" (?insert@?$Tree@H@@QAEXH@Z) referenced in function _main

for three different functions (insert, default constructor, destructor)
Any idea what I'm doing wrong? It doesn't seem to be an issue with VS.


Header:

#pragma once
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

template <class Item>
struct Node
{
	//Default constructor for Node
	//Purpose: Initialize all values
	//Parameters: None
	//Returns: None
	Node();

	//Parameterized constructor for Node
	//Purpose: Initialize all values
	//Parameters: a data Item, and Node pointers for left and right children
	//Returns: None
	Node(Item, Node<Item>*, Node<Item>*);

	//variables
	Item data;
	Node<Item> *lchild;
	Node<Item> *rchild;
};

template <class Item>
class Tree
{

public:
	//Default constructor for Tree
	//Purpose: Initialize all values
	//Parameters: None
	//Returns: None
	Tree();



	//insert
	//Purpose: To add a value to tree
	//Parameters: A const reference to an Item
	//Returns: None
	void insert(Item);

	//copy
	//Purpose: To copy values
	//Parameters: Node pointer
	//Returns: None
	void copy(Node<Item>*);

	//chop
	//Purpose: Delete tree
	//Parameters: Node pointer
	//Returns: None
	void chop(Node<Item>*);

	//Copy constructor
	//Purpose: create new Tree
	//Parameters: A Tree object
	//Returns: Tree
	Tree(const Tree&);

	//Destructor
	//Purpose: Clean up data, delete tree
	//Parameters: None
	//Returns: None
	~Tree();

	//operator=
	//Purpose: Overload assignment operator
	//Parameters: a const ref to a Tree object
	//Returns: Tree
	const Tree<Item>&operator=(const Tree&);

	//inOrderTraverse
	//Purpose: To traverse the tree in order
	//Parameters: A Node pointer
	//Returns: None
	//void inOrderTraverse(Item);


private:
	Node<Item> *root;
};




.cpp:


#include "Tree.h"

template <class Item>
Node<Item>::Node()
{
	data = 0;
	lchild = nullptr;
	rchild = nullptr;
}

template <class Item>
Node<Item>::Node(Item _data, Node<Item> *_lchild, Node<Item> *_rchild)
{
	data = _data;
	lchild = _lchild;
	rchild = _rchild;
}

template <class Item>
Tree<Item>::Tree()
{
	root = nullptr;
}


template <class Item>
void Tree<Item>::insert(Item item)
{
	Node<Item> *new_node = new Node<Item>();
	new_node->data = item;

	if (root == nullptr)
	{
		root = new_node;
	}
	else
	{
		Node<Item> *p = root;
		Node<Item> *q = nullptr;
		while (p->data != item)
		{
			q = p;
			if (item < p->data)
			{
				p = p->lchild;
			}
			else if (item > p->data)
			{
				p = p->rchild;
			}
		}
		if (p->data == item)
		{
			cout << "Duplicate Data" << endl;
		}
		else
		{
			if (item < q->data)
			{
				q->lchild = new_node;
			}
			else
			{
				q->rchild = new_node;
			}
		}

	}
}


template <class Item>
void Tree<Item>::copy(Node<Item> *c)
{
	if (c)
	{
		insert(c->data);
		copy(c->lchild);
		copy(c->rchild);
	}
}

template <class Item>
void Tree<Item>::chop(Node<Item> *c)
{
	if (c)
	{
		chop(c->lchild);
		chop(c->rchild);
		delete c;
	}
}

template <class Item>
Tree<Item>::Tree(const Tree& t)
{
	root = nullptr;
	copy(t.root);
}

template <class Item>
Tree<Item>::~Tree()
{
	chop(root);
}

template <class Item>
const Tree<Item>&Tree<Item>::operator=(const Tree& t)
{
	if (this != &t)
	{
		chop(root);
		root = nullptr;
		copy(t.root);
	}
	return *this;
}





Driver:


#include "Tree.h"

int main()
{
	//variables for data
	string file;
	ifstream infile(file);
	Tree<int> myTree;
	int d = 0;

	//ask user to enter filename
	cout << "Please enter the file you wish to open: " << endl;
	getline(cin, file);
	infile.open(file.c_str());

	//make sure filename is valid
	while (!infile)
	{
		cout << "Error opening file, please enter the name of the file you wish to open: " << endl;
		getline(cin, file);
		infile.open(file.c_str());
	}

	//if file is good, build tree
	while (!infile.eof())
	{
		myTree.insert(d);
		infile >> d;
		cout << d << endl;
	}

	//cout << "Traverse" << endl;
	//inOrderTraverse(d);

	system("PAUSE");
	return 0;
}

[Moschops]

https://stackoverflow.com/questions/8752837/undefined-reference-to-template-class-constructor