Question

This my my successor func:

int 
BalancedTree::successor( TreeNode *node ) // successor is the left-most child of its right subtree,
{ 
  TreeNode *tmp = node;
  int successorVal = -1;
  tmp = tmp->m_RChild;

  if( NULL != tmp )
  {
    while( NULL != tmp->m_LChild )
      tmp = tmp->m_LChild;

    // now at left most child of right subtree
    successorVal = tmp->m_nodeData;
  }

  return successorVal;

} // successor()

my instructor gave us a file filled with random data. I place all this data into the tree, the insert method works, but once the remove method starts, the successor function at some point returns the same value of the the node I’m looking for a successor for. This shouldn’t be able to happen correct? is my successor function correct? If you want to see the remove method just mention it.

Answer 1

Your definition of successor is flawed already: if the node doesn’t have a right node the successor is one of its ancestors: the first one whose left child is the node or one of its ancestors. Only if no such ancestor exists there is mo successor. Personally I would return an iterator to the node but otherwise the code seems to be OK.