Question

I am getting a few errors that I don’t know about and have spent entirely to much time pulling my hair out. Here is my Header:

#ifndef MYBSTREE_H
#define MYBSTREE_H

#include "abstractbstree.h"
#include "MyBSTreeFunc.h"
using namespace std;

template<typename T>
class TreeNode
{
  public:
    T m_data;
    TreeNode* m_right;
    TreeNode* m_left;
};

template<typename T>
class MyBSTree:public AbstractBSTree<T>       //LINE 18
{
  private:

    TreeNode<T>* m_root;

  public:


    void MyBSTree();

    int size() const;

    bool isEmpty() const;

    int height() const;

    const T& findMax() const;

    const T& findMin() const;

    int contains(const T& x) const;

    void clear();

    void insert(const T& x);

    void remove(const T& x);

    void printPreOrder() const;

    void printPostOrder() const;

    void print() const;     
};

#endif

And my implementation file:

Line 1-6

void MyBSTree()
{
  m_root -> m_data = NULL;
  m_root -> m_right = NULL;
  m_root -> m_left = NULL;
}

Line 13-21

template<typename T>
bool MyBSTree<T>::isEmpty() const
{
  if (m_root== NULL)
    return true;

  else
    return false;
}

Line 28-35

template < typename T >
const T& MyBSTree<T>::findMax() const
{
  TreeNode* p = m_root;
  while(p -> m_right != NULL)
    p = p -> m_right;
  return p;
}

The error for line 3 in the implementation says ‘m_root’ was not declared in this scope. But it’s cool with lines 4 and 5. I’m guessing because m_data isn’t a pointer? I don’t know.

Next, Line 14, and 21, and quite a few others say that it expected an initializer before the ‘<‘ token. I assume they are all the same issue so I only put a few here.

Finally, it says for line 18 in the header: “template struct MyBSTree redeclared as a different kind of symbol.” It then says Line 1 of my implementation is a previous declaration of ‘void MyBSTree”. I am assuming those go together.

Thanks for all the help.

Answer 1

You need to fix your constructor declaration:

template < typename T >
classMyBSTree
{
  ... // some stuff
public:
  MyBSTree(); // no return type
  ... // some stuff
};

You alse need to fix your constructor:

template < typename T >
MyBSTree::MyBSTree() // proper ctor definition
{
  m_root -> m_data = T(); // use the initializer for that data type
  m_root -> m_right = NULL;
  m_root -> m_left = NULL;
}