Question

i get those errors when i try to compile a simple AVL tree program :

no matching function for call to A::max(A*&, A*&)
candidates are: int A::max(A&, A&)
request for member 'levels' in 'b', wich is of non-class type 'A*' 

Here is the method that cause the problems :

void A::simpleLeftRotation(A & tree){
   A* b = tree.leftNode;
   tree.leftNode = b->RightNode;
   b->rightNode = &tree;
   tree.levels = 1 + max(tree.leftNode, tree.rightNode); // Problem 1
   b.levels = 1 + max(b.rightNode, tree); // Problem 2
   tree = b;       
}

And here are my class Members :

A* righNode;
A* leftNode;
int levels;
int element;

In the line :

b.levels = 1 + max(b.rightNode, tree);

if i use the -> insted of the point operator i get :

no matching function for call to A::max(A*&, A&)
candidates are: int A::max(A&, A&)

I dont know what i am doing wrong.
Thank you.

Answer 1

Although you didn’t show us the declarations for all the types, I suspect this will fix the problem:

tree.levels = 1 + max(*(tree.leftNode), *(tree.rightNode));
b.levels = 1 + max(*(b.rightNode), tree);

Originally, you were passing pointers in when the max function expects references. Hence, a type mismatch leading to your errors. So you need to dereference your pointers as shown.