Delete node method not actually deleting node in binary search tree. C++

Question

When I call my removeNode method, it shows to delete the node locally and set it to null in the debugger, but when I look at the tree in the debugger the node that should have been deleted is still there. When I print the tree the node that should have been deleted prints, but the int and string assigned to the struct it points to print out gibberish instead.

I've tried using free() and delete but neither actually deleted the node.

bool BinTree::addNode(int id, string info, DataNode *add_node) {
    auto *temp_node = new DataNode;
    temp_node->data.id = id;
    temp_node->data.information = info;
    temp_node->left = temp_node->right = nullptr;

    if(id < add_node->data.id){
        if(!add_node->left){
            add_node->left = new DataNode;
            add_node->left = temp_node;
            count++;
        }else{
            addNode(id, info, add_node->left);
        }
    }else{
        if(!add_node->right){
            add_node->right = new DataNode;
            add_node->right = temp_node;
            count++;
        }else{
            addNode(id, info, add_node->right);
        }
    }
}

bool BinTree::removeNode(int id, DataNode *temp_root) {
    cout << "Searching to remove: " << id << endl;
    if(temp_root == nullptr){
        return false;
    }
    else if(id < temp_root->data.id) {
        removeNode(id, (temp_root->left);
    }
    else if(id > temp_root->data.id){
        removeNode(id, temp_root->right);
    }
    else{
        //no child
        if(temp_root->left == nullptr && temp_root->right == nullptr){
            cout << "Deleting no children node" << endl;            //DEBUG ONLY
            cout << "Temp root address:" << temp_root << endl;      //DEBUG ONLY
            delete temp_root;
            temp_root->data.id = 123456;                            //DEBUG ONLY
            cout << "no child deleted" << endl;                     //DEBUG ONLY
            count--;
        }
        //one child
        else if(temp_root->left == nullptr){
            cout << "Deleting 1 child node" << endl;
            DataNode *temp_node = temp_root;
            temp_root = temp_root->right;
            delete temp_node;
            temp_node = nullptr;
            count--;
        }
        else if(temp_root->right == nullptr){
            cout << "Deleting 1 child node" << endl;
            DataNode *temp_node = temp_root;
            temp_root = temp_root->left;
            free(temp_node);
            temp_node = nullptr;
            count--;
        }
        //two children
        else if(temp_root->left && temp_root->right){
            cout << "Deleting 2 child node" << endl;
            DataNode temp_node = minValueNode(temp_root->right);
            temp_root->data = temp_node.data;
            removeNode(temp_node.data.id, temp_root->right);
        }
        return true;
    }
}

DataNode BinTree::minValueNode(DataNode *temp_node) {
    while(temp_node->left){
        temp_node = temp_node->left;
    }
    return *temp_node;
}

I have some debug output in the method to verify that the temp_root address that it is deleting is the same address that the tree has for the given node, and that is correct. It is just not deleting it from the actual tree.

Answer 1

Personally I would write the remove to return the new value of a link.

void removeNode(int id) {
    root = removeNode(id, root);
}
Node* removeNode(int id, Node* n) {
    if (n == nullptr) {
        return nullptr;
    }

    if (id < n->id) {
        n->left = removeNode(id, n->left);
        return n;
    }
    else if (n->id < id) {
        n->right = removeNode(id, n->right);
        return n;
    }
    else if (n->left == null) {
         Node* result = n->right;
         delete n;
         return result;
    }
    else if (n->right == null) {
         Node* result = n->left;
         delete n;
         return result;
    }
    else {
         int v = findSmallestValue(n->right);
         n->right = removeNode(v, n->right);
         n->id = v;
         return n;
    }
}