Функция для нахождения количества элементов в бинарном дереве

#include <stack>
class Node
{ public:
int value;
Node* left;
Node* right;
};
int count(Node tree) { ... }
int main()
{
Node* root = new Node();
root>
left = new Node();
root>
left>
left = new Node();
root>
left>
right = new Node();
root>
left>
right>
right = new Node();
root>
right = new Node();
int result = count(root);
printf("%d\n", result);
return 0;
}

int count(Node * tree)
{
    if (tree == NULL)
        return 0;
    return count(tree->right) + count(tree->left) + 1;
}

int count(Node * tree)
{
   unsigned int counter = 0;
   stack <Node*> st;
  do
  {
    while (tree != 0)
    {
      st.push(tree);
      tree = tree->left;
    }
    if (st.empty()) return counter-1;
    tree=st.top();
    st.pop();
    if ((tree->right == NULL))++counter;
    if (tree->left == NULL) ++counter;
    tree = tree->right;
  }
  while (true);
}