Binary Tree header file

I am creating a binary tree header file, but only using class (not struct). This is what I have but I get an error and I don't understand how to fix it. Error:
Main.cpp: In function `int main(int, char **)':
BinaryTree.h:21: `class binaryTree::node * binaryTree::root' is private
Main.cpp:12: within this context
BinaryTree.h:21: `class binaryTree::node * binaryTree::root' is private
Main.cpp:15: within this context

Code:

using namespace std;


#ifndef BINARYTREE_H
#define BINARYTREE_H




class binaryTree
{
 private:
     class node
    {
      public:
        int data;
        node *left;
        node *right;
        void addNode(int key, node *n);


    };




  node *root; // the root
  void inorder(node *n);
   void binaryTree::addNode(int key, node *n);


 public:


  void addNode(int key);
  int getHeight(node *n);
  node getRoot();
  binaryTree();
  binaryTree(int data);


};


#endif

Showing us Main.cpp would probably be a good first step

It appears that you're trying to use root from main instead of calling getRoot() like you're supposed to.
However getRoot is a little broken at the moment. It needs to return a pointer.