Thread: BST delete function

Code:

void tree1::remove(int coX, int coY)
{
    //Locate the element
    bool found = false;
    if(isEmpty())
    {
        cout<<" This Tree is empty! "<<endl;
        return;
    }
    tree_node* curr;
    tree_node* parent;
    curr = root;
    while(curr != NULL)
    {
         if(curr->x == coX && curr->y == coY)
         {
            found = true;
            break;
         }
         else
         {
             parent = curr;
             if(coX>curr->x) curr = curr->right;
             else curr = curr->left;
         }
    }
    if(!found)
		 {
        cout<<" Data not found! "<<endl;
        return;
    }


		 // 3 cases :
    // 1. We're removing a leaf node
    // 2. We're removing a node with a single child
    // 3. we're removing a node with 2 children

    // Node with single child
    if((curr->left == NULL && curr->right != NULL)|| (curr->left != NULL
&& curr->right == NULL))
    {
       if(curr->left == NULL && curr->right != NULL)
       {
           if(parent->left == curr)
           {
             parent->left = curr->right;
             delete curr;
           }
           else
           {
             parent->right = curr->right;
             delete curr;
           }
       }
       else // left child present, no right child
       {
          if(parent->left == curr)
           {
             parent->left = curr->left;
             delete curr;
           }
           else
           {
             parent->right = curr->left;
             delete curr;
           }
       }
     return;
    }

		 //We're looking at a leaf node
		 if( curr->left == NULL && curr->right == NULL)
		 {
        if(parent->left == curr) parent->left = NULL;
        else parent->right = NULL;
		 		 delete curr;
		 		 return;
		  }


    //Node with 2 children
    // replace node with smallest value in right subtree
    if (curr->left != NULL && curr->right != NULL)
    {
        tree_node* chkr;
        chkr = curr->right;
        if((chkr->left == NULL) && (chkr->right == NULL))
        {
            curr = chkr;
            delete chkr;
            curr->right = NULL;
        }
        else // right child has children
        {
            //if the node's right child has a left child
            // Move all the way down left to locate smallest element

            if((curr->right)->left != NULL)
            {
                tree_node* lcurr;
                tree_node* lcurrp;
                lcurrp = curr->right;
                lcurr = (curr->right)->left;
                while(lcurr->left != NULL)
                {
                   lcurrp = lcurr;
                   lcurr = lcurr->left;
                }
		 		 		 		 curr->x = lcurr->x;
								 curr->y = lcurr->y;
								 
                delete lcurr;
                lcurrp->left = NULL;
           }
           else
           {
               tree_node* tmp;
               tmp = curr->right;
               curr->x = tmp->x;
			   curr->y = tmp->y;
		 		 		    curr->right = tmp->right;
               delete tmp;
           }

        }
		 return;
    }

}

Above is my function to delete a node from a tree,

when I run it in Visual Studio I get this error, Run-Time Check Failure #3 - The variable 'parent' is being used without being initialized.

I been looking at the code and I dont see anything wrong.

Can some please help me out?

EDIT:

I think the issue is when the node to be removed is a root node and it doesnt have any children.

Hopefully this will be useful

EDIT:

I solved the issue