Thread: Error in binary tree

I do not know what I am missing in my code that causes this following error:

Code:

Error E2285 TreeProgram.cpp 40: Could not find a match for 'Tree::Tree(string)' in function Tree::InsertTree(Tree * &,string)

This is my code.

Code:

#include <iostream>
#include <string>
using namespace std;

class Tree
{
	public:
  		int item;
	 	Tree* root; 	
		Tree* left;
		Tree* right;

	
	int countTree( Tree* root );
	void InsertTree(Tree *&root, string newItem );	  
};

Tree::Tree(){
	root = new Tree;
	
	root->item = 0;
	root->left = NULL;
	root->right = NULL;
}
		
int Tree::countTree( Tree* root ) {

    if ( root == NULL )
          return 0;  
	 else {
           int count = 1;   
	   count += countTree(root->left);                                               
           count += countTree(root->right);                                      
			  return count;  
	 }
}  


void Tree::InsertTree(Tree *&root, string newItem) {

  if ( root == NULL ){
 	 root = new Tree( newItem ); // <<<<<<<<<<<HERE IS THE PROBLEM <<<
     	return;
 }
   else if ( newItem < root->item ) {
      InsertTree( root->left, newItem );
   }
   else {
      InsertTree( root->right, newItem );
   }
} 
 
int main ()
{
 	Tree* root; 	
	int loop=0;
  	int num;
  	while(loop == 0){
  		cout << " Select an Option:" << endl;  
  		cout << "(1) Enter a new calculation string." << endl;  
  		cout << "(2) Print the current tree in infix notation." << endl;  
  		cout << "(3) Print the current tree in prefix notation." << endl;  
  		cout << "(4) Print the current tree in postfix notation." << endl;  
  		cout << "(5) Calculate the result of the current tree." << endl;  
  		cout << "(6) Exit the program." << endl;  
  		cout << " " << endl;  
  		cin >> num;
		
		
		if ( num ==6){
			break;
		}
   }
  return 0;
}