Deleting node from BST without using generics - binary-search-tree

Question

I can't seem to find the correct logic to delete node from binary search tree.
public void delete(int key){
node current=root;
int flag=0;
if(current.data==key){
System.out.println(key+" is deleted");
current.rightchild=null;
current.leftchild=null;
current=null;
}
else{
while(true){
if(current.data>key){
current=current.leftchild;
if(current==null){
flag=1;
break;
}
if(current.data==key){
System.out.println(key+" is deleted");
current.leftchild=null;
current.rightchild=null;
current=null;
break;
}
}
else{
current=current.rightchild;
if(current==null){
flag=1;
break;
}
if(current.data==key){
System.out.println(key+" is deleted");
current.leftchild=null;
current.rightchild=null;
current=null;
break;
}
}
}
}
if(flag==1){`enter code here`
System.out.println(key+" Not Found");
}
}

Answer 1

I use these functions to delete a node in a BST, try it...note that my functions are templated to 3 elements, 1 for ID and 2 for Data.....
template <class T, class U,class V> class Node
{
public:
T ID;
U data1;
V data2;
Node *left;
Node *right;
Node() { left = right = NULL; }
Node(T ID, U data1, V data2)
{
this->ID = ID;
this->data1 = data1;
this->data2 = data2;
left = right = NULL;
}
V getActors()
{
return data2;
}
~Node()
{
delete left;
delete right;
}
};
void Delete(T ID)
{
root = delete_helper(root, ID);
}
Node<T, U,V>* delete_helper(Node<T, U,V>* N, T ID)
{
if (ID < N->ID)
{
N->left = delete_helper(N->left, ID);
return N;
}
else if (ID > N->ID)
{
N->right = delete_helper(N->right, ID);
return N;
}
return Separate(N, ID);
}
Node<T, U,V>* Separate(Node<T, U,V>* N, T ID)
{
Node<T, U,V>* NewNode = NULL;
if ((N->left == NULL) && (N->right == NULL))
{
delete N;
}
else if (N->right == NULL)
{
NewNode = N->left;
delete N;
}
else if (N->left == NULL)
{
NewNode = N->right;
delete N;
}
else
{
NewNode = N;
Node<T, U,V>* R = getRightOf(N->left);
Node<T, U,V>* parent = Parent(R->ID);
N->ID = R->ID;
if (parent != N) {
parent->right = R->left;
}
else {
N->left = R->left;
}
delete R;
}
return NewNode;
}