Question

I am trying to understand what that means
I know that declares a variable to an address of type node and that & gets the address of a variable. I also know that in a function parameter it is a call by reference pointer. But I have never seen it in a variable declaration before…
What does it mean exactly

Node *&ptr = root->mRight

I know about working with pointers and everything I am mostly asking about the Node *& variable type.
Thanks!

Answer 1

On the right, root is a pointer to a node. root->mRight is a member of that node, namely its mright, which is another pointer to a node.

On the left, we declare something (before assigning a value to it with =). If it were Node *ptr, it would be a pointer to a node, but because of that &, it is not such a thing in its own right, it is only a reference, an alias of another such thing that already exists. So ptr is just another name for the pointer root->mRight.