标准库头文件 <map>

 

C++

语言

标准库头文件

自立与有宿主实现

具名要求

语言支持库

概念库 (C++20)

诊断库

工具库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

输入/输出库

本地化库

正则表达式库 (C++11)

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> <coroutine>	<cfloat> <cstdint> <new> <source_location>	<typeinfo> <exception> <initializer_list> <version>	<csignal> <csetjmp> <cstdarg>
概念
<concepts>
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> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
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>
范围
<ranges>
算法
<algorithm>	<execution>
数值
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<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>	<stop_token> <semaphore>	<latch> <barrier>
C 兼容
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

此头文件是容器库的一部分。

类
map	键值对的集合，按照键排序，键是唯一的 (类模板)
multimap	键值对的集合，按照键排序 (类模板)
函数
operator==operator!=operator<operator<=operator>operator>=	按照字典顺序比较 map 中的值 (函数模板)
std::swap(std::map)	特化 std::swap 算法 (函数模板)
operator==operator!=operator<operator<=operator>operator>=	按照字典顺序比较 multimap 中的值 (函数模板)
std::swap(std::multimap)	特化 std::swap 算法 (函数模板)

概要

#include <initializer_list>
 
namespace std {
    template <class Key, class T, class Compare = less<Key>,
              class Allocator = allocator<pair<const Key, T> > >
        class map;
 
    template <class Key, class T, class Compare, class Allocator>
        bool operator==(const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator< (const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator!=(const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator> (const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator>=(const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator<=(const map<Key,T,Compare,Allocator>& x,
                        const map<Key,T,Compare,Allocator>& y);
 
    template <class Key, class T, class Compare, class Allocator>
        void swap(map<Key,T,Compare,Allocator>& x,
                  map<Key,T,Compare,Allocator>& y);
 
 
    template <class Key, class T, class Compare = less<Key>,
              class Allocator = allocator<pair<const Key, T> > >
        class multimap;
 
    template <class Key, class T, class Compare, class Allocator>
        bool operator==(const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator< (const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator!=(const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator> (const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator>=(const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
    template <class Key, class T, class Compare, class Allocator>
        bool operator<=(const multimap<Key,T,Compare,Allocator>& x,
                        const multimap<Key,T,Compare,Allocator>& y);
 
    template <class Key, class T, class Compare, class Allocator>
        void swap(multimap<Key,T,Compare,Allocator>& x,
                  multimap<Key,T,Compare,Allocator>& y);
}

类 std::map

template <class Key, class T, class Compare = less<Key>,
          class Allocator = allocator<pair<const Key, T> > >
class map {
public:
    // 类型：
    typedef Key                                                 key_type;
    typedef T                                                   mapped_type;
    typedef pair<const Key, T>                                  value_type;
    typedef Compare                                             key_compare;
    typedef Allocator                                           allocator_type;
    typedef value_type&                                         reference;
    typedef const value_type&                                   const_reference;
    typedef /* 由实现定义 */                                     iterator;
    typedef /* 由实现定义 */                                     const_iterator; 
    typedef /* 由实现定义 */                                     size_type;
    typedef /* 由实现定义 */                                     difference_type;
    typedef typename allocator_traits<Allocator>::pointer       pointer;
    typedef typename allocator_traits<Allocator>::const_pointer const_pointer;
    typedef std::reverse_iterator<iterator>                     reverse_iterator;
    typedef std::reverse_iterator<const_iterator>               const_reverse_iterator;
 
    class value_compare {
        friend class map;
    protected:
        Compare comp;
        value_compare(Compare c) : comp(c) {}
    public:
        typedef bool        result_type;
        typedef value_type  first_argument_type;
        typedef value_type  second_argument_type;
        bool operator()(const value_type& x, const value_type& y) const {
            return comp(x.first, y.first);
        }
    };
 
    explicit map(const Compare& comp = Compare(),
                 const Allocator& = Allocator());
    template <class InputIterator>
        map(InputIterator first, InputIterator last,
            const Compare& comp = Compare(), const Allocator& = Allocator());
    map(const map<Key,T,Compare,Allocator>& x);
    map(map<Key,T,Compare,Allocator>&& x);
    explicit map(const Allocator&);
    map(const map&, const Allocator&);
    map(map&&, const Allocator&);
    map(initializer_list<value_type>,
        const Compare& = Compare(),
        const Allocator& = Allocator());
 
    ~map();
 
    map<Key,T,Compare,Allocator>&
        operator=(const map<Key,T,Compare,Allocator>& x);
    map<Key,T,Compare,Allocator>&
        operator=(map<Key,T,Compare,Allocator>&& x);
    map& operator=(initializer_list<value_type>);
 
    allocator_type get_allocator() const noexcept;
 
 
    // 迭代器：
    iterator                begin() noexcept;
    const_iterator          begin() const noexcept;
    iterator                end() noexcept;
    const_iterator          end() const noexcept;
 
    reverse_iterator        rbegin() noexcept;
    const_reverse_iterator  rbegin() const noexcept;
    reverse_iterator        rend() noexcept;
    const_reverse_iterator  rend() const noexcept;
 
    const_iterator          cbegin() noexcept;
    const_iterator          cend() noexcept;
    const_reverse_iterator  crbegin() const noexcept;
    const_reverse_iterator  crend() const noexcept;
 
    // 容量：
    bool      empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // 元素访问：
    T& operator[](const key_type& x);
    T& operator[](key_type&& x);
    T&       at(const key_type& x);
    const T& at(const key_type& x) const;
 
    // 修改器：
    template <class... Args> pair<iterator, bool> emplace(Args&&... args);
    template <class... Args> 
        iterator emplace_hint(const_iterator position, Args&&... args);
    pair<iterator, bool> insert(const value_type& x);
    template <class P> pair<iterator, bool> insert(P&& x);
        iterator insert(const_iterator position, const value_type& x);
    template <class P>
        iterator insert(const_iterator position, P&&);
    template <class InputIterator>
        void insert(InputIterator first, InputIterator last);
    void insert(initializer_list<value_type>);
 
    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    iterator erase(const_iterator first, const_iterator last);
    void swap(map<Key,T,Compare,Allocator>&);
    void clear() noexcept;
 
    // 观察器：
    key_compare   key_comp() const;
    value_compare value_comp() const;
 
    // map 操作：
    iterator        find(const key_type& x);
    const_iterator  find(const key_type& x) const;
    size_type       count(const key_type& x) const;
 
    iterator        lower_bound(const key_type& x);
    const_iterator  lower_bound(const key_type& x) const;
    iterator        upper_bound(const key_type& x);
    const_iterator  upper_bound(const key_type& x) const;
 
    pair<iterator,iterator> 
        equal_range(const key_type& x);
    pair<const_iterator,const_iterator> 
        equal_range(const key_type& x) const;
};

类 std::multimap

template <class Key, class T, class Compare = less<Key>,
          class Allocator = allocator<pair<const Key, T> > >
class multimap {
public:
    // 类型：
    typedef Key                                                 key_type;
    typedef T                                                   mapped_type;
    typedef pair<const Key, T>                                  value_type;
    typedef Compare                                             key_compare;
    typedef Allocator                                           allocator_type;
    typedef value_type&                                         reference;
    typedef const value_type&                                   const_reference;
    typedef /* 由实现定义 */                                     iterator;
    typedef /* 由实现定义 */                                     const_iterator; 
    typedef /* 由实现定义 */                                     size_type;
    typedef /* 由实现定义 */                                     difference_type;
    typedef typename allocator_traits<Allocator>::pointer       pointer;
    typedef typename allocator_traits<Allocator>::const_pointer const_pointer;
    typedef std::reverse_iterator<iterator>                     reverse_iterator;
    typedef std::reverse_iterator<const_iterator>               const_reverse_iterator;
 
    class value_compare {
        friend class multimap;
    protected:
        Compare comp;
        value_compare(Compare c) : comp(c) {}
    public:
        typedef bool        result_type;
        typedef value_type  first_argument_type;
        typedef value_type  second_argument_type;
        bool operator()(const value_type& x, const value_type& y) const {
            return comp(x.first, y.first);
        }
    };
 
    explicit multimap(const Compare& comp = Compare(),
                 const Allocator& = Allocator());
    template <class InputIterator>
        multimap(InputIterator first, InputIterator last,
            const Compare& comp = Compare(), const Allocator& = Allocator());
    multimap(const multimap<Key,T,Compare,Allocator>& x);
    multimap(multimap<Key,T,Compare,Allocator>&& x);
    explicit multimap(const Allocator&);
    multimap(const multimap&, const Allocator&);
    multimap(multimap&&, const Allocator&);
    multimap(initializer_list<value_type>,
        const Compare& = Compare(),
        const Allocator& = Allocator());
 
    ~multimap();
 
    multimap<Key,T,Compare,Allocator>&
        operator=(const multimap<Key,T,Compare,Allocator>& x);
    multimap<Key,T,Compare,Allocator>&
        operator=(multimap<Key,T,Compare,Allocator>&& x);
    multimap& operator=(initializer_list<value_type>);
 
    allocator_type get_allocator() const noexcept;
 
 
    // 迭代器：
    iterator                begin() noexcept;
    const_iterator          begin() const noexcept;
    iterator                end() noexcept;
    const_iterator          end() const noexcept;
 
    reverse_iterator        rbegin() noexcept;
    const_reverse_iterator  rbegin() const noexcept;
    reverse_iterator        rend() noexcept;
    const_reverse_iterator  rend() const noexcept;
 
    const_iterator          cbegin() noexcept;
    const_iterator          cend() noexcept;
    const_reverse_iterator  crbegin() const noexcept;
    const_reverse_iterator  crend() const noexcept;
 
    // 容量：
    bool      empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // 修改器：
    template <class... Args> pair<iterator, bool> emplace(Args&&... args);
    template <class... Args> iterator emplace_hint(const_iterator position, Args&&... args);
    pair<iterator, bool> insert(const value_type& x);
    template <class P> pair<iterator, bool> insert(P&& x);
        iterator insert(const_iterator position, const value_type& x);
    template <class P>
        iterator insert(const_iterator position, P&&);
    template <class InputIterator>
        void insert(InputIterator first, InputIterator last);
    void insert(initializer_list<value_type>);
 
    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    iterator erase(const_iterator first, const_iterator last);
    void swap(multimap<Key,T,Compare,Allocator>&);
    void clear() noexcept;
 
    // 观察器：
    key_compare   key_comp() const;
    value_compare value_comp() const;
 
    // multimap 操作：
    iterator        find(const key_type& x);
    const_iterator  find(const key_type& x) const;
    size_type       count(const key_type& x) const;
 
    iterator        lower_bound(const key_type& x);
    const_iterator  lower_bound(const key_type& x) const;
    iterator        upper_bound(const key_type& x);
    const_iterator  upper_bound(const key_type& x) const;
 
    pair<iterator,iterator> 
        equal_range(const key_type& x);
    pair<const_iterator,const_iterator> 
        equal_range(const key_type& x) const;
};