Writing a binary tree class in Managed C++ - visual-c++

Question

I'm trying to figure out how to create a binary tree class in Managed C++ for a school project. I've found really good examples in unmanaged C++ and some in C#, so I have been able to get a fairly good understanding ow what's going on, but I just can't seem to figure it out in Managed C++. What I'd like to find out is: why am I getting the stack overflow (see below), and is this a wise approach? Here's my class:
#pragma once
#include "stdafx.h"
#include <iostream>
#include <deque>
#include <climits>
using namespace std;
using namespace System;
using namespace System::Collections;
ref struct Node
{
int data;
Node ^parent;
Node ^left;
Node ^right;
// constructors
// default constructor
Node (){}
// constructor that takes a node with no leafs
// a constructor that accepts a new node with no children
Node(int input)
{
Node ^node = gcnew Node(input);
node->data =input;
node->left = nullptr;
node->right = nullptr;
node->parent = nullptr;
}
// method to create a new Node
Node ^newNode(int data)
{
Node ^node = gcnew Node;
node->data = data;
node->left = nullptr;
node->right = nullptr;
node->parent = nullptr;
return node;
}
// method that inserts a new node into an existing tree
Node ^insertNode(Node ^node, int input)
{
Node ^p;
Node ^returnNode;
if (node == nullptr)
{
returnNode = newNode(input);
returnNode->parent = p;
return returnNode;
}
if (input <= node->data)
{
p = node;
node->left = insertNode(node->left, input);
}
else
{
p = node;
node->right = insertNode(node->right, input);
}
return node;
}
};
And when I create a new instance, and try to add a node, I get a stack overflow exception.
#include "stdafx.h"
#include "GenericNodeClass.h"
#include "BinarySearchTreeClass.h"
using namespace std;
using namespace System;
int main ()
{
BinarySearchTreeClass^ BTree = gcnew BinarySearchTreeClass();
Node ^newNode = gcnew Node(7);
newNode = newNode->insertNode(newNode, 6); // this just looks stupid
return 0;
}

Answer 1

In your Node constructor...
Node(int input)
{
...you unconditionally call the Node constructor...
Node ^node = gcnew Node(input);
That can't end well. Why are you constructing a new Node in the Node constructor? When the Node constructor is called, it is called to construct the *this object--instead of creating a new Node, you should initialize the current instance.
Likewise in your insertNode member function--it already has access to the *this object; there's no need to pass it via a separate parameter.