2.Containers::reverse_iterator

• https://cplusplus.com/reference/iterator/reverse_iterator/

template <class Iterator> 
class reverse_iterator: public ft::iterator<typename ft::iterator_traits<Iterator>::iterator_category,
                                            typename ft::iterator_traits<Iterator>::value_type,
                                            typename ft::iterator_traits<Iterator>::difference_type,
                                            typename ft::iterator_traits<Iterator>::pointer,
                                            typename ft::iterator_traits<Iterator>::reference>
                                        
{
    public:
        //Member_types
        typedef Iterator iterator_type;
           
        typedef typename iterator_traits<Iterator>::iterator_category   iterator_category;
        typedef typename iterator_traits<Iterator>::value_type          value_type;
        typedef typename iterator_traits<Iterator>::difference_type     difference_type;
        typedef typename iterator_traits<Iterator>::pointer             pointer;
        typedef typename iterator_traits<Iterator>::reference           reference;
};

• 클래스 상속 받고 멤버 변수 타입 설정하는 이유

 protected:
     iterator_type current_state;

---

• 구현해야하는 함수들

• 참고 소스코드 gcc
  https://github.com/gcc-mirror/gcc/blob/54c1bf7801758caf2ff54917e79a8c239643061c/libstdc%2B%2B-v3/include/bits/stl_iterator.h
  line 85 ~

  explicit keyword
  원하지 않은 형변환이 일어나지 않도록 제한하는 키워드이다.
  https://dydtjr1128.github.io/cpp/2019/07/13/Cpp-explicit-keyowrd.html