Syntax Errors when using Scope Resolution Operator

Question

I keep getting a syntax error

"error: expected ';' before "a""

on the line AVL_Tree<val_type>::node_type a; using the Cygwin gcc compiler under Netbeans.

in class "MyMap.h"

#include "AVL_Tree.h"
template <class key_type,class mapped_type>
class MyMap
{
public:
    class iterator
    {
        private:
            AVL_Tree<val_type>::node_type a;
    };
};

in file "AVL_Tree.h"

 template <class T>

 class AVL_Tree
 {
 public:
    struct AVLNode
    {
        int balanceFactor;
        T element;
        AVLNode * left;
        AVLNode * right;

        AVLNode(T key)
        {
            left = 0;
            right = 0;
            element = key;
            balanceFactor = 0;
        }
       typedef AVLNode * node_type;
    };

I was under the impression that I was able to access the "node_type" using the scope operator because the typedef in AVL_Tree is public. The syntax error isn't being very helpful in telling what exactly is going on. Any help is greatly aprreciated.

Answer 1

You need to use typename because node_type is a dependent type. Also, node_type is inside AVLNode :

typename AVL_Tree<val_type>::AVLNode::node_type a;