STL之迭代器实现

#ifndef __ITERATOR_H#define __ITERATOR_H#include"iterator_traits.h"#include<iostream>template<class Container>class back_insert_iterator{protected:Container* container;public:typedef output_iterator_tag_h iterator_category;typedef void value_type;typedef void difference_type;typedef void pointer;typedef void reference;explicit back_insert_iterator(Container& x) :container(&x){}back_insert_iterator<Container>& operator=(const typename Container::value_type& value){container->push_back(value);return *this;}back_insert_iterator<Container>& operator*(){ return *this; }back_insert_iterator<Container>& operator++(){ return *this; }back_insert_iterator<Container>& operator++(int){ return *this; }};template<class Container>inline back_insert_iterator<Container>& back_inserter(Container& x){return back_insert_iterator<Container>(x);}template<class Container>class front_insert_iterator{protected:Container* container;public:typedef output_iterator_tag_h iterator_category;typedef void value_type;typedef void difference_type;typedef void pointer;typedef void reference;explicit front_insert_iterator(Container& x) :container(&x){}front_insert_iterator<Container>& operator=(const typename Container::value_type& value){container.push_front(value);return *this;}front_insert_iterator<Container>& operator*(){ return *this; }front_insert_iterator<Container>& operator++(){ return *this; }front_insert_iterator<Container>& operator++(int){ return *this; }};template<class Container>front_insert_iterator<Container>& front_inserter(Container& x){return front_insert_iterator<Container>(x);}template<class Container>class insert_iterator{protected:Container* container;typename Container::iterator iter;public:typedef output_iterator_tag_h iterator_category;typedef void value_type;typedef void difference_type;typedef void pointer;typedef void reference;insert_iterator(Container& x,typename Container::iterator i):container(&x), iter(i){}insert_iterator<Container>& operator=(const typename Container::value_type& value){iter = container->insert(iter, value);return *this;}insert_iterator<Container>& operator*(){ return *this; }insert_iterator<Container>& operator++(){ return *this; }insert_iterator<Container>& operator++(int){ return *this; }};template<class Container,class Iterator>insert_iterator<Container>& inserter(Container& x, Iterator i){typedef typename Container::iterator iter;return insert_iterator<Container>(x, iter(i));}template<class Iterator>class reverse_iterator{protected:Iterator current;public:typedef typename iterator_trait<Iterator>::iterator_category iterator_category;typedef typename iterator_trait<Iterator>::value_type value_type;typedef typename iterator_trait<Iterator>::difference_type difference_type;typedef typename iterator_trait<Iterator>::pointer pointer;typedef typename iterator_trait<Iterator>::reference reference;typedef Iterator iterator_type;typedef reverse_iterator<Iterator> self;public:reverse_iterator(){}explicit reverse_iterator(iterator_type x) :current(x){}reverse_iterator(const self& x) :current(x.current){}iterator_type base()const{ return current; }reference operator*()const{Iterator tmp = current;return *--tmp;}pointer operator->()const{return &(operator*());}self& operator++(){--current;return *this;}self operator++(int){self tmp = *this;--current;return tmp;}self& operator--(){++current;return *this;}self operator--(int){self tmp = *this;++current;return tmp;}self operator+(difference_type n)const{return self(current - n);}self& operator+=(difference_type n){current -= n;return *this;}self operator-(difference_type n)const{return self(current + n);}self& operator-=(difference_type n){current += n;return *this;}reference operator[](difference_type n)const{return *(*this + n);}};template<class T,class Distance=ptrdiff_t>class istream_iterator{protected:std::istream* stream;T value;bool end_marker;void read(){end_marker = (*stream) ? true : false;if (end_marker)*stream >> value;end_marker = (*stream) ? true : false;}public:typedef input_iterator_tag_h iterator_category;typedef T value_type;typedef Distance difference_type;typedef const T* pointer;typedef const T& reference;istream_iterator() :stream(&std::cin), end_marker(false){}istream_iterator(std::istream& s) :stream(&s){ read(); }reference operator*()const{ return value; }pointer operator->()const{ return &(operator*()); }istream_iterator<T, Distance>& operator++(){read();return *this;}istream_iterator<T, Distance>  operator++(int){istream_iterator<T, Distance> tmp = *this;read();return tmp;}bool _M_equal(const istream_iterator<T,Distance>& __x)const{return (end_marker == __x.end_marker) && (!end_marker || stream == __x.stream);}};template<class T,class Distance>inline bool operator==(const istream_iterator<T, Distance>& x, const istream_iterator<T, Distance>& y){return x._M_equal(y);}template<class T, class Distance>inline bool operator!=(const istream_iterator<T, Distance>& x, const istream_iterator<T, Distance>& y){return !x._M_equal(y);}template<class T>class ostream_iterator{protected:std::ostream* stream;const char* string;public:typedef output_iterator_tag_h iterator_category;typedef void value_type;typedef void difference_type;typedef void pointer;typedef void reference;ostream_iterator(std::ostream& s) :stream(&s), string(0){}ostream_iterator(std::ostream& s, const char* c) :stream(&s), string(c){}ostream_iterator<T>& operator=(const T& value){*stream << value;if (string)*stream << string;return *this;}ostream_iterator<T>& operator*(){ return *this; }ostream_iterator<T>& operator->(){ return &(operator*()); }ostream_iterator<T>& operator++(int){ return *this; }};#endif