标准库头文件 <set>

 

C++

编译器支持

独立和托管

语言

标准库

标准库头文件

命名要求

功能测试宏 (C++20)

语言支持库

概念库 (C++20)

元编程库 (C++11)

诊断库

通用实用程序库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

并发支持库 (C++11)

执行支持库 (C++26)

技术规范

符号索引

外部库

 

标准库头文件

语言支持
<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <stdfloat> (C++23) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11) <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
概念
<concepts> (C++20)
诊断
<stdexcept> <stacktrace> (C++23)	<cassert>	<cerrno>	<system_error> (C++11)
内存管理
<memory>	<memory_resource> (C++17)	<scoped_allocator> (C++11)
元编程
<type_traits> (C++11)	<ratio> (C++11)
通用实用程序
<utility> <tuple> (C++11) <optional> (C++17) <variant> (C++17)	<any> (C++17) <debugging> (C++26) <expected> (C++23) <bitset>	<functional> <typeindex> (C++11) <execution> (C++17)	<charconv> (C++17) <format> (C++20) <bit> (C++20)
字符串
<string_view> (C++17) <string>	<cctype> <cwctype>	<cstring> <cwchar>	<cuchar> (C++11)
容器
<array> (C++11) <deque> <forward_list> (C++11) <list>	<vector> <map> <set> <unordered_map> (C++11)	<unordered_set> (C++11) <queue> <stack> <flat_map> (C++23)	<flat_set> (C++23) <span> (C++20) <mdspan> (C++23) <inplace_vector> (C++26)
迭代器
<iterator>
范围
<ranges> (C++20)	<generator> (C++23)
算法
<algorithm>	<numeric>
数值
<cfenv> (C++11) <complex>	<random> (C++11) <valarray>	<cmath> <linalg> (C++26)	<numbers> (C++20)
时间
<chrono> (C++11)	<ctime>
本地化
<locale>	<clocale>	<codecvt> (C++11/17/26*)	<text_encoding> (C++26)
输入/输出
<iosfwd> <iostream> <ios> <streambuf>	<istream> <ostream> <iomanip> <print> (C++23)	<sstream> <spanstream> (C++23) <fstream> <syncstream> (C++20)	<filesystem> (C++17) <cstdio> <cinttypes> (C++11) <strstream> (C++98/26*)
正则表达式
<regex> (C++11)
并发支持
<stop_token> (C++20) <thread> (C++11) <atomic> (C++11) <rcu> (C++26)	<stdatomic.h> (C++23) <mutex> (C++11) <shared_mutex> (C++14)	<condition_variable> (C++11)   <semaphore> (C++20) <latch> (C++20)	<barrier> (C++20) <future> (C++11) <hazard_pointer> (C++26)
C 兼容性
<cstdbool> (C++11/17/20*)   <ccomplex> (C++11/17/20*)	<ctgmath> (C++11/17/20*)	<cstdalign> (C++11/17/20*)	<ciso646> (直到 C++20)

 

此头文件是 容器 库的一部分。

包含
<compare> (C++20)	三路比较运算符 支持
<initializer_list> (C++11)	std::initializer_list 类模板
类
set	唯一键的集合，按键排序 (类模板)
multiset	键的集合，按键排序 (类模板)
函数
operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20)	按字典序比较两个 set 的值 (函数模板)
std::swap(std::set)	专门化 std::swap 算法 (函数模板)
erase_if(std::set) (C++20)	删除满足特定条件的所有元素 (函数模板)
operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20 中已移除)(C++20)	按字典序比较两个 multiset 的值 (函数模板)
std::swap(std::multiset)	专门化 std::swap 算法 (函数模板)
erase_if(std::multiset) (C++20)	删除满足特定条件的所有元素 (函数模板)
范围访问
begincbegin (C++11)(C++14)	返回指向容器或数组开头的迭代器 (函数模板)
endcend (C++11)(C++14)	返回指向容器或数组末尾的迭代器 (函数模板)
rbegincrbegin (C++14)	返回指向容器或数组开头的反向迭代器 (函数模板)
rendcrend (C++14)	返回指向容器或数组反向末尾的迭代器 (函数模板)
sizessize (C++17)(C++20)	返回容器或数组的大小 (函数模板)
empty (C++17)	检查容器是否为空 (函数模板)
data (C++17)	获取指向底层数组的指针 (函数模板)

概要

#include <compare>
#include <initializer_list>
 
namespace std {
  // class template set
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  class set;
 
  template<class Key, class Compare, class Allocator>
  bool operator==(const set<Key, Compare, Allocator>& x,
                  const set<Key, Compare, Allocator>& y);
  template<class Key, class Compare, class Allocator>
  /*synth-three-way-result*/<Key> operator<=>(const set<Key, Compare, Allocator>& x,
                                              const set<Key, Compare, Allocator>& y);
 
  template<class Key, class Compare, class Allocator>
  void swap(set<Key, Compare, Allocator>& x,
            set<Key, Compare, Allocator>& y) noexcept(noexcept(x.swap(y)));
 
  // erasure for set
  template<class Key, class Compare, class Allocator, class Predicate>
  typename set<Key, Compare, Allocator>::size_type erase_if(
    set<Key, Compare, Allocator>& c,
    Predicate pred);
 
  // class template multiset
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  class multiset;
 
  template<class Key, class Compare, class Allocator>
  bool operator==(const multiset<Key, Compare, Allocator>& x,
                  const multiset<Key, Compare, Allocator>& y);
  template<class Key, class Compare, class Allocator>
  /*synth-three-way-result*/<Key> operator<=>(const multiset<Key, Compare, Allocator>& x,
                                              const multiset<Key, Compare, Allocator>& y);
 
  template<class Key, class Compare, class Allocator>
  void swap(multiset<Key, Compare, Allocator>& x,
            multiset<Key, Compare, Allocator>& y) noexcept(noexcept(x.swap(y)));
 
  // erasure for multiset
  template<class Key, class Compare, class Allocator, class Predicate>
  typename multiset<Key, Compare, Allocator>::size_type erase_if(
    multiset<Key, Compare, Allocator>& c,
    Predicate pred);
 
  namespace pmr {
    template<class Key, class Compare = less<Key>>
    using set = std::set<Key, Compare, polymorphic_allocator<Key>>;
 
    template<class Key, class Compare = less<Key>>
    using multiset = std::multiset<Key, Compare, polymorphic_allocator<Key>>;
  }
}

类模板 std::set

namespace std {
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  class set
  {
  public:
    // types
    using key_type               = Key;
    using key_compare            = Compare;
    using value_type             = Key;
    using value_compare          = Compare;
    using allocator_type         = Allocator;
    using pointer                = typename allocator_traits<Allocator>::pointer;
    using const_pointer          = typename allocator_traits<Allocator>::const_pointer;
    using reference              = value_type&;
    using const_reference        = const value_type&;
    using size_type              = /* implementation-defined */;
    using difference_type        = /* implementation-defined */;
    using iterator               = /* implementation-defined */;
    using const_iterator         = /* implementation-defined */;
    using reverse_iterator       = std::reverse_iterator<iterator>;
    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
    using node_type              = /* unspecified */;
    using insert_return_type     = /*insert-return-type*/<iterator, node_type>;
 
    // construct/copy/destroy
    set()
      : set(Compare())
    {
    }
    explicit set(const Compare& comp, const Allocator& = Allocator());
    template<class InputIter>
    set(InputIter first,
        InputIter last,
        const Compare& comp = Compare(),
        const Allocator&    = Allocator());
    template<container-compatible-range<value_type> R>
    set(from_range_t,
        R&& rg,
        const Compare& comp = Compare(),
        const Allocator&    = Allocator());
    set(const set& x);
    set(set&& x);
    explicit set(const Allocator&);
    set(const set&, const type_identity_t<Allocator>&);
    set(set&&, const type_identity_t<Allocator>&);
    set(initializer_list<value_type>,
        const Compare&   = Compare(),
        const Allocator& = Allocator());
    template<class InputIter>
    set(InputIter first, InputIter last, const Allocator& a)
      : set(first, last, Compare(), a)
    {
    }
    template<container-compatible-range<value_type> R>
      set(from_range_t, R&& rg, const Allocator& a))
        : set(from_range, std::forward<R>(rg), Compare(), a)
    {
    }
    set(initializer_list<value_type> il, const Allocator& a)
      : set(il, Compare(), a)
    {
    }
    ~set();
    set& operator=(const set& x);
    set& operator=(set&& x) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
                                       is_nothrow_move_assignable_v<Compare>);
    set& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;
 
    // iterators
    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() const noexcept;
    const_iterator cend() const noexcept;
    const_reverse_iterator crbegin() const noexcept;
    const_reverse_iterator crend() const noexcept;
 
    // capacity
    bool empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // modifiers
    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);
    pair<iterator, bool> insert(value_type&& x);
    template<class K>
    pair<iterator, bool> insert(K&& x);
    iterator insert(const_iterator position, const value_type& x);
    iterator insert(const_iterator position, value_type&& x);
    template<class K>
    iterator insert(const_iterator position, K&& x);
    template<class InputIter>
    void insert(InputIter first, InputIter last);
    template<container-compatible-range<value_type> R>
    void insert_range(R&& rg);
    void insert(initializer_list<value_type>);
 
    node_type extract(const_iterator position);
    node_type extract(const key_type& x);
    template<class K>
    node_type extract(K&& x);
    insert_return_type insert(node_type&& nh);
    iterator insert(const_iterator hint, node_type&& nh);
 
    iterator erase(iterator position)
      requires(!same_as<iterator, const_iterator>);
    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    template<class K>
    size_type erase(K&& x);
    iterator erase(const_iterator first, const_iterator last);
    void swap(set&) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
                               is_nothrow_swappable_v<Compare>);
    void clear() noexcept;
 
    template<class C2>
    void merge(set<Key, C2, Allocator>& source);
    template<class C2>
    void merge(set<Key, C2, Allocator>&& source);
    template<class C2>
    void merge(multiset<Key, C2, Allocator>& source);
    template<class C2>
    void merge(multiset<Key, C2, Allocator>&& source);
 
    // observers
    key_compare key_comp() const;
    value_compare value_comp() const;
 
    // set operations
    iterator find(const key_type& x);
    const_iterator find(const key_type& x) const;
    template<class K>
    iterator find(const K& x);
    template<class K>
    const_iterator find(const K& x) const;
 
    size_type count(const key_type& x) const;
    template<class K>
    size_type count(const K& x) const;
 
    bool contains(const key_type& x) const;
    template<class K>
    bool contains(const K& x) const;
 
    iterator lower_bound(const key_type& x);
    const_iterator lower_bound(const key_type& x) const;
    template<class K>
    iterator lower_bound(const K& x);
    template<class K>
    const_iterator lower_bound(const K& x) const;
 
    iterator upper_bound(const key_type& x);
    const_iterator upper_bound(const key_type& x) const;
    template<class K>
    iterator upper_bound(const K& x);
    template<class K>
    const_iterator upper_bound(const K& x) const;
 
    pair<iterator, iterator> equal_range(const key_type& x);
    pair<const_iterator, const_iterator> equal_range(const key_type& x) const;
    template<class K>
    pair<iterator, iterator> equal_range(const K& x);
    template<class K>
    pair<const_iterator, const_iterator> equal_range(const K& x) const;
  };
 
  template<class InputIter,
           class Compare   = less</*iter-value-type*/<InputIter>>,
           class Allocator = allocator</*iter-value-type*/<InputIter>>>
  set(InputIter, InputIter, Compare = Compare(), Allocator = Allocator())
    -> set</*iter-value-type*/<InputIter>, Compare, Allocator>;
 
  template<ranges::input_range R,
           class Compare   = less<ranges::range_value_t<R>>,
           class Allocator = allocator<ranges::range_value_t<R>>>
  set(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
    -> set<ranges::range_value_t<R>, Compare, Allocator>;
 
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  set(initializer_list<Key>, Compare = Compare(), Allocator = Allocator())
    -> set<Key, Compare, Allocator>;
 
  template<class InputIter, class Allocator>
  set(InputIter, InputIter, Allocator) -> set</*iter-value-type*/<InputIter>,
                                              less</*iter-value-type*/<InputIter>>,
                                              Allocator>;
 
  template<ranges::input_range R, class Allocator>
  set(from_range_t, R&&, Allocator)
    -> set<ranges::range_value_t<R>, less<ranges::range_value_t<R>>, Allocator>;
 
  template<class Key, class Allocator>
  set(initializer_list<Key>, Allocator) -> set<Key, less<Key>, Allocator>;
}

类模板 std::multiset

namespace std {
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  class multiset
  {
  public:
    // types
    using key_type               = Key;
    using key_compare            = Compare;
    using value_type             = Key;
    using value_compare          = Compare;
    using allocator_type         = Allocator;
    using pointer                = typename allocator_traits<Allocator>::pointer;
    using const_pointer          = typename allocator_traits<Allocator>::const_pointer;
    using reference              = value_type&;
    using const_reference        = const value_type&;
    using size_type              = /* implementation-defined */;
    using difference_type        = /* implementation-defined */;
    using iterator               = /* implementation-defined */;
    using const_iterator         = /* implementation-defined */;
    using reverse_iterator       = std::reverse_iterator<iterator>;
    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
    using node_type              = /* unspecified */;
 
    // construct/copy/destroy
    multiset()
      : multiset(Compare())
    {
    }
    explicit multiset(const Compare& comp, const Allocator& = Allocator());
    template<class InputIter>
    multiset(InputIter first,
             InputIter last,
             const Compare& comp = Compare(),
             const Allocator&    = Allocator());
    template<container-compatible-range<value_type> R>
    multiset(from_range_t,
             R&& rg,
             const Compare& comp = Compare(),
             const Allocator&    = Allocator());
    multiset(const multiset& x);
    multiset(multiset&& x);
    explicit multiset(const Allocator&);
    multiset(const multiset&, const type_identity_t<Allocator>&);
    multiset(multiset&&, const type_identity_t<Allocator>&);
    multiset(initializer_list<value_type>,
             const Compare&   = Compare(),
             const Allocator& = Allocator());
    template<class InputIter>
    multiset(InputIter first, InputIter last, const Allocator& a)
      : multiset(first, last, Compare(), a)
    {
    }
    template<container-compatible-range<value_type> R>
      multiset(from_range_t, R&& rg, const Allocator& a))
        : multiset(from_range, std::forward<R>(rg), Compare(), a)
    {
    }
    multiset(initializer_list<value_type> il, const Allocator& a)
      : multiset(il, Compare(), a)
    {
    }
    ~multiset();
    multiset& operator=(const multiset& x);
    multiset& operator=(multiset&& x) noexcept(
      allocator_traits<Allocator>::is_always_equal::value&&
        is_nothrow_move_assignable_v<Compare>);
    multiset& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;
 
    // iterators
    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() const noexcept;
    const_iterator cend() const noexcept;
    const_reverse_iterator crbegin() const noexcept;
    const_reverse_iterator crend() const noexcept;
 
    // capacity
    bool empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // modifiers
    template<class... Args>
    iterator emplace(Args&&... args);
    template<class... Args>
    iterator emplace_hint(const_iterator position, Args&&... args);
    iterator insert(const value_type& x);
    iterator insert(value_type&& x);
    iterator insert(const_iterator position, const value_type& x);
    iterator insert(const_iterator position, value_type&& x);
    template<class InputIter>
    void insert(InputIter first, InputIter last);
    template<container-compatible-range<value_type> R>
    void insert_range(R&& rg);
    void insert(initializer_list<value_type>);
 
    node_type extract(const_iterator position);
    node_type extract(const key_type& x);
    template<class K>
    node_type extract(K&& x);
    iterator insert(node_type&& nh);
    iterator insert(const_iterator hint, node_type&& nh);
 
    iterator erase(iterator position)
      requires(!same_as<iterator, const_iterator>);
    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    template<class K>
    size_type erase(K&& x);
    iterator erase(const_iterator first, const_iterator last);
    void swap(multiset&) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
                                    is_nothrow_swappable_v<Compare>);
    void clear() noexcept;
 
    template<class C2>
    void merge(multiset<Key, C2, Allocator>& source);
    template<class C2>
    void merge(multiset<Key, C2, Allocator>&& source);
    template<class C2>
    void merge(set<Key, C2, Allocator>& source);
    template<class C2>
    void merge(set<Key, C2, Allocator>&& source);
 
    // observers
    key_compare key_comp() const;
    value_compare value_comp() const;
 
    // set operations
    iterator find(const key_type& x);
    const_iterator find(const key_type& x) const;
    template<class K>
    iterator find(const K& x);
    template<class K>
    const_iterator find(const K& x) const;
 
    size_type count(const key_type& x) const;
    template<class K>
    size_type count(const K& x) const;
 
    bool contains(const key_type& x) const;
    template<class K>
    bool contains(const K& x) const;
 
    iterator lower_bound(const key_type& x);
    const_iterator lower_bound(const key_type& x) const;
    template<class K>
    iterator lower_bound(const K& x);
    template<class K>
    const_iterator lower_bound(const K& x) const;
 
    iterator upper_bound(const key_type& x);
    const_iterator upper_bound(const key_type& x) const;
    template<class K>
    iterator upper_bound(const K& x);
    template<class K>
    const_iterator upper_bound(const K& x) const;
 
    pair<iterator, iterator> equal_range(const key_type& x);
    pair<const_iterator, const_iterator> equal_range(const key_type& x) const;
    template<class K>
    pair<iterator, iterator> equal_range(const K& x);
    template<class K>
    pair<const_iterator, const_iterator> equal_range(const K& x) const;
  };
 
  template<class InputIter,
           class Compare   = less</*iter-value-type*/<InputIter>>,
           class Allocator = allocator</*iter-value-type*/<InputIter>>>
  multiset(InputIter, InputIter, Compare = Compare(), Allocator = Allocator())
    -> multiset</*iter-value-type*/<InputIter>, Compare, Allocator>;
 
  template<ranges::input_range R,
           class Compare   = less<ranges::range_value_t<R>>,
           class Allocator = allocator<ranges::range_value_t<R>>>
  multiset(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
    -> multiset<ranges::range_value_t<R>, Compare, Allocator>;
 
  template<class Key, class Compare = less<Key>, class Allocator = allocator<Key>>
  multiset(initializer_list<Key>, Compare = Compare(), Allocator = Allocator())
    -> multiset<Key, Compare, Allocator>;
 
  template<class InputIter, class Allocator>
  multiset(InputIter, InputIter, Allocator)
    -> multiset</*iter-value-type*/<InputIter>,
                less</*iter-value-type*/<InputIter>>,
                Allocator>;
 
  template<ranges::input_range R, class Allocator>
  multiset(from_range_t, R&&, Allocator)
    -> multiset<ranges::range_value_t<R>, less<ranges::range_value_t<R>>, Allocator>;
 
  template<class Key, class Allocator>
  multiset(initializer_list<Key>, Allocator) -> multiset<Key, less<Key>, Allocator>;
}

缺陷报告

以下行为变更缺陷报告已追溯应用于先前发布的 C++ 标准。

DR	应用于	已发布的行为	正确行为
LWG 214	C++98	成员 find、lower_bound、upper_bound 以及 std::set 和 std::multiset 的 equal_range 的声明 与关联容器的要求不匹配	已更正