| #ifndef ITERATORS_H |
| #define ITERATORS_H |
| |
| #include <iterator> |
| |
| template <class It> |
| class input_iterator |
| { |
| It it_; |
| |
| template <class U> friend class input_iterator; |
| public: |
| typedef std::input_iterator_tag iterator_category; |
| typedef typename std::iterator_traits<It>::value_type value_type; |
| typedef typename std::iterator_traits<It>::difference_type difference_type; |
| typedef It pointer; |
| typedef typename std::iterator_traits<It>::reference reference; |
| |
| It base() const {return it_;} |
| |
| input_iterator() : it_() {} |
| explicit input_iterator(It it) : it_(it) {} |
| template <class U> |
| input_iterator(const input_iterator<U>& u) :it_(u.it_) {} |
| |
| reference operator*() const {return *it_;} |
| pointer operator->() const {return it_;} |
| |
| input_iterator& operator++() {++it_; return *this;} |
| input_iterator operator++(int) |
| {input_iterator tmp(*this); ++(*this); return tmp;} |
| |
| friend bool operator==(const input_iterator& x, const input_iterator& y) |
| {return x.it_ == y.it_;} |
| friend bool operator!=(const input_iterator& x, const input_iterator& y) |
| {return !(x == y);} |
| }; |
| |
| template <class T, class U> |
| inline |
| bool |
| operator==(const input_iterator<T>& x, const input_iterator<U>& y) |
| { |
| return x.base() == y.base(); |
| } |
| |
| template <class T, class U> |
| inline |
| bool |
| operator!=(const input_iterator<T>& x, const input_iterator<U>& y) |
| { |
| return !(x == y); |
| } |
| |
| #endif // ITERATORS_H |