Subclass Mess on a vague Binary Tree Question - c++

Question

So, I'm taking data structures and algorithms and I'm trying to answer the following question:
(20 marks) Exercise 6.7. Create a subclass of BinaryTree whose nodes have fields for storing preorder, post-order, and in-order numbers. Write methods preOrderNumber(), inOrderNumber(), and postOrderNumbers() that assign these numbers correctly. These methods should each run in O(n) time.
Now... I'm confused about what the question is even asking. Are they asking me to store an array in each Node that records the preOrder, inOrder and postOrder values of the whole tree??? Or are they asking me to create a subclass of Node that contains an integer that's hold the Next value, according to a preOrder, inOrder or postOrder value, relative to the Node we're in...
So, I went with the former and assumed that they wanted the array. But the trouble now is that I've created a new version of Node and I'm trying to call this preOrderNumber() function at the bottom but I get the following error:
BTNode.h contains the code I used in a previous question to construct a binary tree. It just defines a class Node with a left, right, and parent pointer, as well as an add() function to add new values to the tree, and a preOrderNEXT() function that gets the next value in the tree according to that transversal order. the same is true for inOrderNEXT(), and postOrderNEXT()
#include <iostream>
#include "BTNode.h"
#include <vector>
using namespace std;
class BinaryTree : public Node {
public:
vector<int> preOrderNumbers;
vector<int> inOrderNumbers;
vector<int> postOrderNumbers;
BinaryTree(int x);
~BinaryTree();
int preOrderNumber();
int inOrderNumber();
int postOrderNumber();
};
BinaryTree::BinaryTree(int x) : Node(x) {}
BinaryTree::~BinaryTree() {}
int BinaryTree::preOrderNumber() {
Node* next_Node = preOrderNEXT(this);
while (next_Node != NULL) {
preOrderNumbers.push_back(next_Node->data);
next_Node = preOrderNEXT(next_Node);
}
}
int BinaryTree::inOrderNumber() {
Node* next_Node = inOrderNEXT(this);
while (next_Node != NULL) {
inOrderNumbers.push_back(next_Node->data);
next_Node = inOrderNEXT(next_Node);
}
}
int BinaryTree::postOrderNumber() {
Node* next_Node = postOrderNEXT(this);
while (next_Node != NULL) {
postOrderNumbers.push_back(next_Node->data);
next_Node = postOrderNEXT(next_Node);
}
}
int main() {
Node* BinaryT = new BinaryTree(rand() % 1000);
int arr[] = { 71, 6, 28, 49, 41, 42, 88, 72, 21, 84, 85, 94, 59, 29, 2, 97, 33, 23, 78 };
cout << "We add these integers, one by one, using a for loop to the binary tree:\n" << endl;
cout << "[ 60, ";
for (int i = 0; i < (sizeof(arr) / sizeof(arr[0])); i++) {
BinaryT->add(arr[i]);
cout << arr[i] << ", ";
}
int x = BinaryT->preOrderNumber();
}

Answer 1

OKAY, So yea I think I found out the real crux of this question and I'll answer this here for anyone else stuck in this situation.
The key to making sense out of this question is to visit its location in the textbook. The course coordinator ripped this question out of the textbook and doesn't provide any context. In Pat Morin's book Open Data Structure, An Introduction, on page 149 there's an illustration 6.10.
So, what this question IS ACTUALLY ASKING you to do is write a subclass for the Binary Tree Nodes such that each Node holds an integer that keeps track of its position within the corresponding traversal type. So maybe your Node would be visited 3rd in preOrder, 4th in an inOrder, and 2nd in a postOrder traversal. So that Node should hold a 3, a 4, and a 2 in the corresponding position. And then you need a function to update that position in O(n) time.