c++ - No member function declaration in class template -

i have template class named skiplist , nested class named iterator in it.

skiplist follows following definition:

template <typename key_t, typename mapped_t, size_t maxlevel = 5> class skiplist {   typedef std::pair<key_t, mapped_t> valuetype;   public:    class iterator   {       iterator (const iterator &);       iterator &operator=(const iterator &);       iterator &operator++();       iterator operator++(int);       iterator &operator--();       iterator operator--(int);      private:       //some members   }; 

iterator has copy constructor , declaring outside class after definition this:

template <typename key_t, typename mapped_t,size_t maxlevel> skiplist<key_t,mapped_t,maxlevel>::iterator(const skiplist<key_t,mapped_t,maxlevel>::iterator &that) 

but following error:

skiplist.cpp:134:100: error: iso c++ forbids declaration of ‘iterator’ no type [-fpermissive] skiplist.cpp:134:100: error: no ‘int skiplist<key_t, mapped_t, maxlevel>::iterator(const skiplist<key_t, mapped_t, maxlevel>::iterator&)’ member function declared in class ‘skiplist<key_t, mapped_t, maxlevel>’ 

what wrong?

try this:

template <typename key_t, typename mapped_t,size_t maxlevel> skiplist<key_t,mapped_t,maxlevel>::iterator::iterator    (const skiplist<key_t,mapped_t,maxlevel>::iterator &that) { ... 

you forgot qualify iterator copy constructor skiplist::iterator::iterator, looking skiplist member function called skiplist::iterator, hence error "no member function".