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Getting nullptr error when trying to delete a node from a binary tree

rlake (18)
Hello,

I am trying to delete a node from a binary tree and am getting a nullptr error. If anyone would please give me some pointers on what to look for, I would greatly appreciate it.

The function is below:

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  void BinTree::deleteItem(int val)
{
	MyNode *trailCurrent = nullptr;
	MyNode *current = root; //pointer to traverse the tree
	MyNode *temp;

	bool found = false;
	if (root == nullptr)
	{
		cout << "Cannot delete from the empty tree." << endl;
		return;
	}
	//find the node to be deleted
	while (current != nullptr && !found)
	{
		if (current->info == val)  //if value is found
			found = true;
		else  //while value is not found
		{
			trailCurrent = current;
			if (val < current->info)  //if value is less than current's info
				current = current->llink; //traverse the left side of the tree
			else
				current = current->rlink;  //otherwise traverse the right side of the tree
		}
	}

	if (current = nullptr)
		cout << "The item to be deleted is not in the tree." << endl;

	else if (found) //delete pointers to node
	{
		//node is a leaf
		trailCurrent = current;
		if (current->llink == NULL && current->rlink == NULL)
		{
			if (trailCurrent->llink == current)
				trailCurrent->llink = NULL;
			else
				trailCurrent->rlink = NULL;
			delete current;
		}
		//node has 2 children
		else if ((current->llink != NULL) && (current->rlink != NULL))
		{
	
			current = trailCurrent->llink;
//			trailCurrent = NULL;
			while (current->rlink != NULL)
			{
				trailCurrent = current;
				current = current->rlink;
			}
			trailCurrent->info = current->info;
			if (trailCurrent == NULL)
				trailCurrent->llink = current->llink;
			else
				trailCurrent->rlink = current->llink;
			delete current;
		}
		//node has 1 child
		else
		{
			if (trailCurrent->llink == NULL)
			{
				temp = trailCurrent;
				trailCurrent = temp->rlink;
				delete temp;
			}
			else
				temp = trailCurrent;
				trailCurrent = temp->llink;
				delete temp;
		}
	}
	
}


Thank you.

Regards,

Ragan
Last edited on
cire (8284)
On line 28, you use = which is assignment instead of == for comparison. Your compiler likely generates a warning for this.
rlake (18)
Thanks!
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