标准库头文件 <iterator>

 

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原子操作库 (C++11)

线程支持库 (C++11)

文件系统库 (C++17)

技术规范

 

标准库头文件

语言支持
<cstddef> <limits> <climits> <version>	<cfloat> <cstdint> <new>	<typeinfo> <exception> <initializer_list>	<csignal> <csetjmp> <cstdarg>
诊断
<stdexcept>	<cassert>	<cerrno>	<system_error>
通用工具
<utility> <memory> <memory_resource> <scoped_allocator>     <compare>	<bitset> <tuple> <optional> <any> <variant>	<type_traits> <ratio> <chrono> <typeindex> <functional>	<ctime> <cstdlib>
字符串
<string> <string_view>	<cctype> <cwctype>	<cwchar> <cuchar>	<cstring> <charconv>
本地化
<locale>	<codecvt>	<clocale>
容器
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
迭代器
<iterator>
算法
<algorithm>	<execution>
数值
<complex> <random>	<valarray> <numeric>	<cfenv> <cmath>
输入/输出
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
正则表达式
<regex>
文件系统
<filesystem>
线程支持
<thread> <atomic>	<mutex> <shared_mutex>	<condition_variable> <future>
C 兼容
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

此头文件是迭代器库的一部分。

类

原语
iterator_traits	为迭代器属性提供统一接口 (类模板)
input_iterator_tag output_iterator_tag forward_iterator_tag bidirectional_iterator_tag random_access_iterator_tag	用于指示迭代器类别的空类类型 (类)
iterator (C++17 中弃用)	简化简单迭代器所要求类型定义的基类 (类模板)
适配器
reverse_iterator	逆序遍历的迭代器适配器 (类模板)
move_iterator (C++11)	解引用到右值引用的迭代器适配器 (类模板)
back_insert_iterator	用于在容器尾部插入的迭代器适配器 (类模板)
front_insert_iterator	用于在容器头部插入的迭代器适配器 (类模板)
insert_iterator	用于插入容器的迭代器适配器 (类模板)
流迭代器
istream_iterator	从 std::basic_istream 读取的输入迭代器 (类模板)
ostream_iterator	写入 std::basic_ostream 的输出迭代器 (类模板)
istreambuf_iterator	从 std::basic_streambuf 读取的输入迭代器 (类模板)
ostreambuf_iterator	写入 std::basic_streambuf 的输出迭代器 (类模板)

函数

适配器
make_reverse_iterator (C++14)	创建拥有从参数推出的类型的 std::reverse_iterator (函数模板)
make_move_iterator (C++11)	创建拥有从参数推出的类型的 std::move_iterator (函数模板)
front_inserter	创建拥有从参数推出的类型的 std::front_insert_iterator (函数模板)
back_inserter	创建拥有从参数推出的类型的 std::back_insert_iterator (函数模板)
inserter	创建拥有从参数推出的类型的 std::insert_iterator (函数模板)
操作
advance	令迭代器前进给定的距离 (函数)
distance	返回二个迭代器间的距离 (函数)
next (C++11)	令迭代器自增 (函数)
prev (C++11)	令迭代器自减 (函数)
范围
begin cbegin (C++11) (C++14)	返回指向容器或数组起始的迭代器 (函数)
end cend (C++11) (C++14)	返回指向容器或数组结尾的迭代器 (函数)
rbegin crbegin (C++14)	返回指向一个容器或数组的逆向迭代器 (函数)
rend crend (C++14)	返回容器或数组的逆向尾迭代器 (函数)
非成员运算符
operator== operator!= operator< operator<= operator> operator>=	比较底层迭代器 (函数模板)
operator+	令迭代器前进 (函数模板)
operator-	计算二个迭代器适配器间的距离 (函数模板)
operator== operator!= operator< operator<= operator> operator>=	比较底层迭代器 (函数模板)
operator+	令迭代器前进 (函数模板)
operator-	计算二个迭代器适配器间的距离 (函数模板)
operator== operator!=	比较两个 istream_iterator (函数模板)
operator== operator!=	比较两个 istreambuf_iterator (函数模板)

概要

namespace std {
    // 原语：
    template<class Iterator> struct iterator_traits;
    template<class T> struct iterator_traits<T*>;
    template<class Category, class T, class Distance = ptrdiff_t,
    class Pointer = T*, class Reference = T&> struct iterator;
 
    struct input_iterator_tag { };
    struct output_iterator_tag { };
    struct forward_iterator_tag: public input_iterator_tag { };
    struct bidirectional_iterator_tag: public forward_iterator_tag { };
    struct random_access_iterator_tag: public bidirectional_iterator_tag { };
 
    // 迭代器操作：
    template <class InputIterator, class Distance>
        void advance(InputIterator& i, Distance n);
    template <class InputIterator>
        typename iterator_traits<InputIterator>::difference_type
        distance(InputIterator first, InputIterator last);
    template <class ForwardIterator>
        ForwardIterator next(ForwardIterator x,
            typename std::iterator_traits<ForwardIterator>::difference_type n = 1);
    template <class BidirectionalIterator>
        BidirectionalIterator prev(BidirectionalIterator x,
            typename std::iterator_traits<BidirectionalIterator>::difference_type n = 1);
 
    // 预定义迭代器：
    template <class Iterator> class reverse_iterator;
    template <class Iterator1, class Iterator2>
        bool operator==(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator<(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator!=(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator>(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator>=(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator<=(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y);
 
    template <class Iterator1, class Iterator2>
        auto operator-(
            const reverse_iterator<Iterator1>& x,
            const reverse_iterator<Iterator2>& y) ->decltype(y.base() - x.base());
    template <class Iterator>
        reverse_iterator<Iterator>
        operator+(
            typename reverse_iterator<Iterator>::difference_type n,
            const reverse_iterator<Iterator>& x);
    template <class Iterator>
        reverse_iterator<Iterator> make_reverse_iterator(Iterator i);
 
    template <class Container> class back_insert_iterator;
    template <class Container>
        back_insert_iterator<Container> back_inserter(Container& x);
 
    template <class Container> class front_insert_iterator;
    template <class Container>
        front_insert_iterator<Container> front_inserter(Container& x);
 
    template <class Container> class insert_iterator;
    template <class Container>
        insert_iterator<Container> inserter(Container& x, typename Container::iterator i);
 
    template <class Iterator> class move_iterator;
    template <class Iterator1, class Iterator2>
        bool operator==(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator!=(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator<(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator<=(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator>(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
    template <class Iterator1, class Iterator2>
        bool operator>=(
            const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
 
    template <class Iterator1, class Iterator2>
        auto operator-(
            const move_iterator<Iterator1>& x,
            const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
    template <class Iterator>
        move_iterator<Iterator> operator+(
            typename move_iterator<Iterator>::difference_type n, 
            const move_iterator<Iterator>& x);
    template <class Iterator>
        move_iterator<Iterator> make_move_iterator(Iterator i);
 
    // 流迭代器：
    template <class T, class charT = char, class traits = char_traits<charT>,
            class Distance = ptrdiff_t>
        class istream_iterator;
    template <class T, class charT, class traits, class Distance>
        bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
            const istream_iterator<T,charT,traits,Distance>& y);
    template <class T, class charT, class traits, class Distance>
        bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
            const istream_iterator<T,charT,traits,Distance>& y);
 
    template <class T, class charT = char, class traits = char_traits<charT> >
        class ostream_iterator;
 
    template<class charT, class traits = char_traits<charT> >
        class istreambuf_iterator;
    template <class charT, class traits>
        bool operator==(const istreambuf_iterator<charT,traits>& a,
            const istreambuf_iterator<charT,traits>& b);
    template <class charT, class traits>
        bool operator!=(const istreambuf_iterator<charT,traits>& a,
            const istreambuf_iterator<charT,traits>& b);
 
    template <class charT, class traits = char_traits<charT> >
        class ostreambuf_iterator;
 
    // 范围访问：
    template <class C> auto begin(C& c) -> decltype(c.begin());
    template <class C> auto begin(const C& c) -> decltype(c.begin());
    template <class C> auto end(C& c) -> decltype(c.end());
    template <class C> auto end(const C& c) -> decltype(c.end());
    template <class T, size_t N> T* begin(T (&array)[N]);
    template <class T, size_t N> T* end(T (&array)[N]);
}

类 std::iterator_traits

template<class Iterator> struct iterator_traits {
    typedef typename Iterator::difference_type      difference_type;
    typedef typename Iterator::value_type           value_type;
    typedef typename Iterator::pointer              pointer;
    typedef typename Iterator::reference            reference;
    typedef typename Iterator::iterator_category    iterator_category;
};
 
template<class T> struct iterator_traits<T*> {
    typedef ptrdiff_t                   difference_type;
    typedef T                           value_type;
    typedef T*                          pointer;
    typedef T&                          reference;
    typedef random_access_iterator_tag  iterator_category;
};
 
template<class T> struct iterator_traits<const T*> {
    typedef ptrdiff_t                   difference_type;
    typedef T                           value_type;
    typedef const T*                    pointer;
    typedef const T&                    reference;
    typedef random_access_iterator_tag  iterator_category;
};

类 std::iterator

template<class Category, class T, class Distance = ptrdiff_t,
         class Pointer = T*, class Reference = T&>
struct iterator {
    typedef T           value_type;
    typedef Distance    difference_type;
    typedef Pointer     pointer;
    typedef Reference   reference;
    typedef Category    iterator_category;
};

迭代器标签

struct input_iterator_tag { };
struct output_iterator_tag { };
struct forward_iterator_tag: public input_iterator_tag { };
struct bidirectional_iterator_tag: public forward_iterator_tag { };
struct random_access_iterator_tag: public bidirectional_iterator_tag { };

类 std::reverse_iterator

template <class Iterator>
class reverse_iterator {
public:
    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>::reference         reference;
    typedef typename iterator_traits<Iterator>::pointer           pointer;
 
    reverse_iterator();
    explicit reverse_iterator(Iterator x);
    template <class U> reverse_iterator(const reverse_iterator<U>& u);
    template <class U> reverse_iterator& operator=(const reverse_iterator<U>& u);
 
    Iterator base() const; // explicit
    reference operator*() const;
    pointer operator->() const;
 
    reverse_iterator& operator++();
    reverse_iterator  operator++(int);
    reverse_iterator& operator--();
    reverse_iterator  operator--(int);
 
    reverse_iterator  operator+ (difference_type n) const;
    reverse_iterator& operator+=(difference_type n);
    reverse_iterator  operator- (difference_type n) const;
    reverse_iterator& operator-=(difference_type n);
 
    /*unspecified*/ operator[](difference_type n) const;
protected:
    Iterator current;
};

类 std::back_insert_iterator

template <class Container>
class back_insert_iterator {
protected:
    Container* container;
public:
    typedef output_iterator_tag iterator_category;
    typedef void                value_type;
    typedef void                difference_type;
    typedef void                pointer;
    typedef void                reference;
    typedef Container           container_type;
 
    explicit back_insert_iterator(Container& x);
    back_insert_iterator<Container>&
        operator=(const typename Container::value_type& value);
    back_insert_iterator<Container>&
        operator=(typename Container::value_type&& value);
 
    back_insert_iterator<Container>& operator*();
    back_insert_iterator<Container>& operator++();
    back_insert_iterator<Container>  operator++(int);
};

类 std::front_insert_iterator

template <class Container>
class front_insert_iterator {
protected:
    Container* container;
public:
    typedef output_iterator_tag iterator_category;
    typedef void                value_type;
    typedef void                difference_type;
    typedef void                pointer;
    typedef void                reference;
    typedef Container           container_type;
 
    explicit front_insert_iterator(Container& x);
    front_insert_iterator<Container>&
    operator=(const typename Container::value_type& value);
    front_insert_iterator<Container>&
    operator=(typename Container::value_type&& value);
 
    front_insert_iterator<Container>& operator*();
    front_insert_iterator<Container>& operator++();
    front_insert_iterator<Container>  operator++(int);
};

类 std::insert_iterator

template <class Container>
class insert_iterator {
protected:
    Container*                   container;
    typename Container::iterator iter;
public:
    typedef output_iterator_tag iterator_category;
    typedef void                value_type;
    typedef void                difference_type;
    typedef void                pointer;
    typedef void                reference;
    typedef Container           container_type;
 
    insert_iterator(Container& x, typename Container::iterator i);
    insert_iterator<Container>&
    operator=(const typename Container::value_type& value);
    insert_iterator<Container>&
    operator=(typename Container::value_type&& value);
 
    insert_iterator<Container>& operator*();
    insert_iterator<Container>& operator++();
    insert_iterator<Container>& operator++(int);
};

类 std::move_iterator

template <class Iterator>
class move_iterator {
public:
    typedef Iterator                                            iterator_type;
    typedef typename iterator_traits<Iterator>::difference_type difference_type;
    typedef Iterator                                            pointer;
    typedef typename iterator_traits<Iterator>::value_type      value_type;
    typedef typename iterator_traits<Iterator>::iterator_category
                                                                iterator_category;
    typedef value_type&&                                        reference;
 
    move_iterator();
    explicit move_iterator(Iterator i);
    template <class U> move_iterator(const move_iterator<U>& u);
    template <class U> move_iterator& operator=(const move_iterator<U>& u);
 
    iterator_type base() const;
    reference operator*() const;
    pointer operator->() const;
 
    move_iterator& operator++();
    move_iterator  operator++(int);
    move_iterator& operator--();
    move_iterator  operator--(int);
 
    move_iterator   operator+(difference_type n) const;
    move_iterator&  operator+=(difference_type n);
    move_iterator   operator-(difference_type n) const;
    move_iterator&  operator-=(difference_type n);
    /*unspecified*/ operator[](difference_type n) const;
 
private:
    Iterator current; // 仅为说明
};