二进制搜索树删除节点

Question

I adapted my code from from this book: Data Structures and Algorithms by Mark Allen Weiss, 3rd edition.

Every time I run it, it crashes. By request I'll add the entire Binary Tree code (its long). Whenever I try to run it in debug mode, I end up cycling between the first three if else statements in the remove() function, and then I end up getting this output:

"Unhandled exception at 0x0007300d in Project 4Draft.exe: 0xC0000005: Access violation reading location 0x003c0000."

I'm pretty sure this is a segfault, just trying to find the source. Also, when I run it, it doesn't step into findMin() , but I included it because its within remove, and It's not fully tested yet. Can anyone help me derive the source?

Here is the remove function:

void remove(const T& x, TreeNode * & tn) const {
    if(tn == NULL)
        return;
    else if(x < tn->data)
        remove(x, tn->left);
    else if(tn->data < x)
        remove(x, tn->right);
    else if(tn->left != NULL && tn->right != NULL) {//Two Children(Swap the min of the right subtree, and swap
        tn->data = findMin(tn->right)->data;
        remove(tn->data,tn->right);
    }
    else{
        TreeNode *oldNode = tn;
        tn = (tn->left != NULL ) ? tn->left : tn->right;
        delete oldNode;
    }

}

here is findMin():

TreeNode * findMin(TreeNode *x) const {
        if(debugMode==true){
        cout << "\nWERE IN FINDMIN\n";
        }
        if(x==NULL){
            return NULL;
        }
        if(x->left==NULL){
            if(debugMode==true){
            cout << x;
            }
            return x;
        }

        return findMin(x->left);
    };

And here is what I call in my test file:

cout << "Checking remove()\n";
    for(int i =SIZE; i>0;i++){
        z.remove(x[i]);
    }
    cout << "DONE Checking remove()\n";

Answer 1

Are you sure that your loop condition is correct?

for(int i =SIZE; i>0;i++){
    z.remove(x[i]);
}
cout << "DONE Checking remove()\n";

Maybe you should write something like:

for(int i = 0; i < SIZE; i++){
    z.remove(x[i]);
}

or

for(int i = SIZE - 1; i >= 0; i--){
    z.remove(x[i]);
}