static TNode *removeRecursive(TNode *pRoot, const void *pKey, CompareFunc compare)
{
int result;
TNode *pNodeSuccessor, *pNodeDelete;
if (pRoot != NULL)
{
if ((result = compare(pRoot->pData, pKey)) > 0)
{
pRoot->pLeft = removeRecursive(pRoot->pLeft, pKey, compare);
}
else if (result < 0)
{
pRoot->pRight = removeRecursive(pRoot->pRight, pKey, compare);
}
else
{
if (pRoot->pLeft == NULL)
{
pNodeDelete = pRoot;
pRoot = pRoot->pRight;
delete pNodeDelete;
}
else if (pRoot->pRight == NULL)
{
pNodeDelete = pRoot;
pRoot = pRoot->pLeft;
delete pNodeDelete;
}
else
{
pNodeSuccessor = getInorderSuccessor(pRoot->pRight);
pRoot->pData = pNodeSuccessor->pData;
pRoot->pRight = removeRecursive(pRoot->pRight, pNodeSuccessor->pData, compare);
}
}
return pRoot;
}
else
{
return NULL;
}
}
struct AVLnode* remove_node(struct AVLnode* root, int data)
{
if (!root)
return root;
// search for element
if (data < root->data)
root->left = remove_node(root->left, data);
else if (data > root->data)
root->right = remove_node(root->right, data);
else
{
// data is found
// node to be deleted is leaf
if (!root->left && !root->right)
{
free(root);
root = NULL;
}
// node to be deleted has one child
else if (!root->right)// has left child
{
struct AVLnode* temp = root;
root = root->left;
free(temp);
}
else if (!root->left)// has right child
{
struct AVLnode* temp = root;
root = root->right;
free(temp);
}
else
{
// node has two children
struct AVLnode* inorderSuccessor = getInorderSuccessor(root->right);
root->data = inorderSuccessor->data;
root->right = remove_node(root->right, inorderSuccessor->data);
}
}
return root;
}