CODEWITHSUNDEEP
c++templatesscopeoperator-overloading
user658096
user658096

Reputation:

Scope Resolution::Nested Template Typename

My overloaded prefix operator is having issues finding the scope.

#ifndef LIST_H
#define LIST_H
#include <iostream>
using namespace std;

template <typename T>
struct node
{
   T data;
   node* next;
   node* prev;
};

template <typename T>
class list
{
   public:
      class iterator
      {
         public:
            iterator() : inode(0) {}
            iterator(node<T>* current) : inode(current) {}

            // overload prefix increment operator (++x)
            iterator& operator ++();
            }    
         private:
            node<T>* inode; // 
      };

      iterator begin();
      iterator end();

   private:
      // pointer to the head of the dclist
      node<T>* head;
};

// constructor
template <typename T>
list<T>::list() {
   head = new node<T>;
   head->next = head;
   head->prev = head;
}

template <typename T> // This function needs proper scope resolution
typename list<T>::iterator::iterator& iterator<T>::operator ++() {
   inode = inode->next;
   return this;
}

// return iterate from beginning //
template <typename T>
typename list<T>::iterator list<T>::begin() { 
   return list<T>::iterator(head->next);
}

// return iterate to end // 
template <typename T>
typename list<T>::iterator list<T>::end() {
   return list<T>::iterator(head);
}

#endif

Upvotes: 1

Views: 1232

Answers (1)

James McNellis
James McNellis

Reputation: 355207

The function name is not properly qualified and the return type has an extra iterator:

template <typename T>
typename list<T>::iterator::iterator& iterator<T>::operator ++()

This needs to be:

template <typename T>
typename list<T>::iterator& list<T>::iterator::operator++()

Note also that using using namespace std; and declaring your own types with names identical to Standard Library names (list, iterator, etc.) can only end in tears. It would behoove you to drop the using namespace std;.

Upvotes: 3

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