Thread: Crashing

Hello,

First of all, this is my code:

Code:

#include <iostream>

using namespace std;

struct TreeNode
{
    int data;
    struct TreeNode *left;
    struct TreeNode *right;

    TreeNode() { left = NULL; right = NULL; }
};

void insertNode(int data, TreeNode* t)
{
    if(data <= t->data)
    {
        // insert left
        if(t->left == NULL)
        {
            cout << "INSERTING LEFT OF " << t->data << endl << endl;
            TreeNode newt;
            newt.data = data;
            t->left = &newt;

        }
        else
            insertNode(data, t->left);
    }
    else
    {
        // insert right
        if(t->right == NULL)
        {
            cout << "INSERTING RIGHT OF " << t->data << endl << endl;
            TreeNode newt;
            newt.data = data;
            t->right = &newt;
        }
        else
            insertNode(data, t->right);
    }
}

int main()
{
    TreeNode a;
    TreeNode b;
    TreeNode c;

    a.data = 5;
    b.data = 50;
    c.data = 20;

    a.right = &b;
    b.left = &c;

    insertNode(80, &a);

    cout << "The right child of the new node is: " << b.right->right << endl;
    cout << b.right->right << endl << endl;

    if(b.right->right == NULL)
        cout << "ITS NULL";
    else
        cout << "ITS... NOT";

    return 0;
}

I've just started out with C++ and I'm playing with binary trees. In InsertNode(), a new Node with the data 80 is added to the right of the 'b' node, meaning that b.right is that new node. Now, when displaying b.right->right (which should be NULL), I'm getting some weird stuff.

The first cout (starting with 'the right child of...') gives me a memory address, the second cout gives me 0. When checking if b.right->right == NULL, I get the message that it's not.

Why is this happening? When I create a new node, both the children are instantiated to NULL but apparently something goes wrong when I do this in the InsertNode() function.