void Delete(int key) {                                  //deletion of an element with given key

        bool check = Search(key);                           //using "Search" function to determine if emlement with given key exists within the tree
        Node* parent = NULL;                                //temporary pointer at parent of the element that's going to be deleted
        Node* temp = root;                                  //element that's going to be deleted

        if (!check) { return; }                             //if there's no element with given key

        else {                                              //there is an element with given key

            while (temp->key != key) {                      //loop to determine the temp and it's parent

                parent = temp;

                if (temp->key < key) { temp = temp->right; }

                else { temp = temp->left; }

            }
            if (temp->right == NULL && temp->left == NULL) {        //if temp has no subtrees

                if (temp = root) { root = NULL; Initialize(); delete temp; return; }        //if temp is the root, root becomes NULL, initialization of a new BST

                else if (parent->right = temp) { parent->right = NULL; delete temp; return; }   //if temp is parent's right child

                else { parent->left = NULL; delete temp; return; }          //if temp is parent's left child
            }
            else if (temp->right == NULL) {                         //if temp has only left subtree

                if (temp == root) { root = temp->left; delete temp; return; }       //if temp is the root, root becomes it's left child

                else if (parent->right == temp) { parent->right = temp->left; delete temp; return; }  //if temp is parent's right child

                else { parent->left = temp->left; delete temp; return; }        //if temp is parent's left child

            }
            else if (temp->left == NULL) {          //if temp has only right subtree

                if (temp == root) { root = temp->right; delete temp; return; }  //if temp is the root, root becomes it's right child

                else if (parent->right == temp) { parent->right = temp->right; delete temp; return; }       //if temp is parent's right child

                else { parent->left = temp->right; delete temp; return; }       //if temp is parent's left child

            }

            //if temp has both subtrees, algorythm that uses predecessor instead of successor

            Node*preparent = temp;              //pointer at temp's predecessor's parent
            Node*child = temp->left;            //pointer at temp's predecessor

            while (child->right != NULL) {      //loop to determine temp's predecessor

                preparent = child;
                child = child->right;

            }

            if (child == temp->left) {          //if predecessor is temp's left child

                if (temp == root) { root = temp->left; root->right = temp->right; delete temp; return; }        //temp is the root

                else if (parent->right == temp) { parent->right = child; delete temp; return; }         //temp is it's parent's right child

                else { parent->left = child; delete temp; return; }         //temp is it's parent's left child

            }

            //if temp's predecessor isn't it's child but grandchild or grandgrandchild or so on

            Node*grandchild = child->left;   //pointer at possible precdecessor's child

            //filling the blank space that appears when we "take out" an node from a tree, that has both subtrees

            if (preparent->right == child) { preparent->right = grandchild; }       //if predecessor is it's parent's right child

            else { preparent->left = grandchild; }              //if predecessor is it's parent's left child

            //after filling the blank space we can delete the node

            child->left = temp->left;           //temp's left child becomes predecessor's left child

            if (temp == root) { root=child; delete temp; return; }      //if temp is the root, predecessor becomes the root

            else if (parent->right == temp) { parent->right = child; delete temp; return; }     //if temp is it's parent's right child

            else { parent->left = child; delete temp; return; }         //if temp is it's parent's left child

        }


    }