标准库标头 <map>
来自cppreference.com
此标头是容器库的一部分。
包含 | |
(C++20) |
三路比较运算符支持 |
(C++11) |
std::initializer_list 类模板 |
类 | |
| 键值对的集合,按照键排序,键是唯一的 (类模板) | |
| 键值对的集合,按照键排序 (类模板) | |
函数 | |
(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20) |
按照字典顺序比较两个 map 的值 (函数模板) |
| 特化 std::swap 算法 (函数模板) | |
(C++20) |
擦除所有满足特定判别标准的元素 (函数模板) |
(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20 移除)(C++20) |
按照字典顺序比较两个 multimap 的值 (函数模板) |
| 特化 std::swap 算法 (函数模板) | |
(C++20) |
擦除所有满足特定判别标准的元素 (函数模板) |
范围访问 | |
(C++11)(C++14) |
返回指向容器或数组起始的迭代器 (函数模板) |
(C++11)(C++14) |
返回指向容器或数组结尾的迭代器 (函数模板) |
(C++14) |
返回指向一个容器或数组的逆向迭代器 (函数模板) |
(C++14) |
返回容器或数组的逆向尾迭代器 (函数模板) |
(C++17)(C++20) |
返回容器或数组的大小 (函数模板) |
(C++17) |
检查容器是否为空 (函数模板) |
(C++17) |
获得指向底层数组的指针 (函数模板) |
概要
#include <compare>
#include <initializer_list>
namespace std {
// 类模板 map
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>
/*synth-three-way-result*/<pair<const Key, T>> 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) noexcept(noexcept(x.swap(y)));
// map 的擦除
template<class Key, class T, class Compare, class Allocator, class Predicate>
typename map<Key, T, Compare, Allocator>::size_type erase_if(
map<Key, T, Compare, Allocator>& c,
Predicate pred);
// 类模板 multimap
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>
/*synth-three-way-result*/<pair<const Key, T>> 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) noexcept(noexcept(x.swap(y)));
// multimap 的擦除
template<class Key, class T, class Compare, class Allocator, class Predicate>
typename multimap<Key, T, Compare, Allocator>::size_type erase_if(
multimap<Key, T, Compare, Allocator>& c,
Predicate pred);
namespace pmr {
template<class Key, class T, class Compare = less<Key>>
using map = std::map<Key, T, Compare, polymorphic_allocator<pair<const Key, T>>>;
template<class Key, class T, class Compare = less<Key>>
using multimap =
std::multimap<Key, T, Compare, polymorphic_allocator<pair<const Key, T>>>;
}
}
类模板 std::map
namespace std {
template<class Key,
class T,
class Compare = less<Key>,
class Allocator = allocator<pair<const Key, T>>>
class map
{
public:
// 类型
using key_type = Key;
using mapped_type = T;
using value_type = pair<const Key, T>;
using key_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 = /* 由实现定义 */;
using difference_type = /* 由实现定义 */;
using iterator = /* 由实现定义 */;
using const_iterator = /* 由实现定义 */;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using node_type = /* 未指明 */;
using insert_return_type = /*insert-return-type*/<iterator, node_type>;
class value_compare
{
protected:
Compare comp;
value_compare(Compare c)
: comp(c)
{
}
public:
bool operator()(const value_type& x, const value_type& y) const
{
return comp(x.first, y.first);
}
};
// 构造/复制/销毁
map()
: map(Compare())
{
}
explicit map(const Compare& comp, const Allocator& = Allocator());
template<class InputIter>
map(InputIter first,
InputIter last,
const Compare& comp = Compare(),
const Allocator& = Allocator());
template<container-compatible-range<value_type> R>
map(from_range_t,
R&& rg,
const Compare& comp = Compare(),
const Allocator& = Allocator());
map(const map& x);
map(map&& x);
explicit map(const Allocator&);
map(const map&, const type_identity_t<Allocator>&);
map(map&&, const type_identity_t<Allocator>&);
map(initializer_list<value_type>,
const Compare& = Compare(),
const Allocator& = Allocator());
template<class InputIter>
map(InputIter first, InputIter last, const Allocator& a)
: map(first, last, Compare(), a)
{
}
template<container-compatible-range<value_type> R>
map(from_range_t, R&& rg, const Allocator& a))
: map(from_range, std::forward<R>(rg), Compare(), a)
{
}
map(initializer_list<value_type> il, const Allocator& a)
: map(il, Compare(), a)
{
}
~map();
map& operator=(const map& x);
map& operator=(map&& x) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
is_nothrow_move_assignable_v<Compare>);
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() const noexcept;
const_iterator cend() const 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
mapped_type& operator[](const key_type& x);
mapped_type& operator[](key_type&& x);
template<class K>
mapped_type& operator[](K&& x);
mapped_type& at(const key_type& x);
const mapped_type& at(const key_type& x) const;
template<class K>
mapped_type& at(const K& x);
template<class K>
const mapped_type& at(const K& 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);
pair<iterator, bool> insert(value_type&& x);
template<class P>
pair<iterator, bool> insert(P&& x);
iterator insert(const_iterator position, const value_type& x);
iterator insert(const_iterator position, value_type&& x);
template<class P>
iterator insert(const_iterator position, P&&);
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);
template<class... Args>
pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);
template<class... Args>
pair<iterator, bool> try_emplace(key_type&& k, Args&&... args);
template<class K, class... Args>
pair<iterator, bool> try_emplace(K&& k, Args&&... args);
template<class... Args>
iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args);
template<class... Args>
iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args);
template<class K, class... Args>
iterator try_emplace(const_iterator hint, K&& k, Args&&... args);
template<class M>
pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);
template<class M>
pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj);
template<class K, class M>
pair<iterator, bool> insert_or_assign(K&& k, M&& obj);
template<class M>
iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj);
template<class M>
iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj);
template<class K, class M>
iterator insert_or_assign(const_iterator hint, K&& k, M&& obj);
iterator erase(iterator position);
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(map&) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
is_nothrow_swappable_v<Compare>);
void clear() noexcept;
template<class C2>
void merge(map<Key, T, C2, Allocator>& source);
template<class C2>
void merge(map<Key, T, C2, Allocator>&& source);
template<class C2>
void merge(multimap<Key, T, C2, Allocator>& source);
template<class C2>
void merge(multimap<Key, T, C2, Allocator>&& source);
// 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;
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-key-type*/<InputIter>>,
class Allocator = allocator</*iter-to-alloc-type*/<InputIter>>>
map(InputIter, InputIter, Compare = Compare(), Allocator = Allocator())
-> map</*iter-key-type*/<InputIter>,
/*iter-mapped-type*/<InputIter>,
Compare,
Allocator>;
template<
ranges::input_range R,
class Compare =
less</*range-key-type*/<R>, class Allocator = allocator</*range-to-alloc-type*/<R>>>
map(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
-> map</*range-key-type*/<R>, /*range-mapped-type*/<R>, Compare, Allocator>;
template<class Key,
class T,
class Compare = less<Key>,
class Allocator = allocator<pair<const Key, T>>>
map(initializer_list<pair<Key, T>>, Compare = Compare(), Allocator = Allocator())
-> map<Key, T, Compare, Allocator>;
template<class InputIter, class Allocator>
map(InputIter, InputIter, Allocator) -> map</*iter-key-type*/<InputIter>,
/*iter-mapped-type*/<InputIter>,
less</*iter-key-type*/<InputIter>>,
Allocator>;
template<ranges::input_range R, class Allocator>
map(from_range_t, R&&, Allocator) -> map</*range-key-type*/<R>,
/*range-mapped-type*/<R>,
less</*range-key-type*/<R>>,
Allocator>;
template<class Key, class T, class Allocator>
map(initializer_list<pair<Key, T>>, Allocator) -> map<Key, T, less<Key>, Allocator>;
}
类模板 std::multimap
namespace std {
template<class Key,
class T,
class Compare = less<Key>,
class Allocator = allocator<pair<const Key, T>>>
class multimap
{
public:
// 类型
using key_type = Key;
using mapped_type = T;
using value_type = pair<const Key, T>;
using key_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 = /* 由实现定义 */;
using difference_type = /* 由实现定义 */;
using iterator = /* 由实现定义 */;
using const_iterator = /* 由实现定义 */;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using node_type = /* 未指明 */;
class value_compare
{
protected:
Compare comp;
value_compare(Compare c)
: comp(c)
{
}
public:
bool operator()(const value_type& x, const value_type& y) const
{
return comp(x.first, y.first);
}
};
// 构造/复制/销毁
multimap()
: multimap(Compare())
{
}
explicit multimap(const Compare& comp, const Allocator& = Allocator());
template<class InputIter>
multimap(InputIter first,
InputIter last,
const Compare& comp = Compare(),
const Allocator& = Allocator());
template<container-compatible-range<value_type> R>
multimap(from_range_t,
R&& rg,
const Compare& comp = Compare(),
const Allocator& = Allocator());
multimap(const multimap& x);
multimap(multimap&& x);
explicit multimap(const Allocator&);
multimap(const multimap&, const type_identity_t<Allocator>&);
multimap(multimap&&, const type_identity_t<Allocator>&);
multimap(initializer_list<value_type>,
const Compare& = Compare(),
const Allocator& = Allocator());
template<class InputIter>
multimap(InputIter first, InputIter last, const Allocator& a)
: multimap(first, last, Compare(), a)
{
}
template<container-compatible-range<value_type> R>
multimap(from_range_t, R&& rg, const Allocator& a))
: multimap(from_range, std::forward<R>(rg), Compare(), a)
{
}
multimap(initializer_list<value_type> il, const Allocator& a)
: multimap(il, Compare(), a)
{
}
~multimap();
multimap& operator=(const multimap& x);
multimap& operator=(multimap&& x) noexcept(
allocator_traits<Allocator>::is_always_equal::value&&
is_nothrow_move_assignable_v<Compare>);
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() const noexcept;
const_iterator cend() const 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>
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);
template<class P>
iterator insert(P&& x);
iterator insert(const_iterator position, const value_type& x);
iterator insert(const_iterator position, value_type&& x);
template<class P>
iterator insert(const_iterator position, P&& 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);
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(multimap&) noexcept(allocator_traits<Allocator>::is_always_equal::value&&
is_nothrow_swappable_v<Compare>);
void clear() noexcept;
template<class C2>
void merge(multimap<Key, T, C2, Allocator>& source);
template<class C2>
void merge(multimap<Key, T, C2, Allocator>&& source);
template<class C2>
void merge(map<Key, T, C2, Allocator>& source);
template<class C2>
void merge(map<Key, T, C2, Allocator>&& source);
// 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;
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-key-type*/<InputIter>>,
class Allocator = allocator</*iter-to-alloc-type*/<InputIter>>>
multimap(InputIter, InputIter, Compare = Compare(), Allocator = Allocator())
-> multimap</*iter-key-type*/<InputIter>,
/*iter-mapped-type*/<InputIter>,
Compare,
Allocator>;
template<ranges::input_range R,
class Compare = less</*range-key-type*/<R>>,
class Allocator = allocator</*range-to-alloc-type*/<R>>>
multimap(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
-> multimap</*range-key-type*/<R>, /*range-mapped-type*/<R>, Compare, Allocator>;
template<class Key,
class T,
class Compare = less<Key>,
class Allocator = allocator<pair<const Key, T>>>
multimap(initializer_list<pair<Key, T>>, Compare = Compare(), Allocator = Allocator())
-> multimap<Key, T, Compare, Allocator>;
template<class InputIter, class Allocator>
multimap(InputIter, InputIter, Allocator)
-> multimap</*iter-key-type*/<InputIter>,
/*iter-mapped-type*/<InputIter>,
less</*iter-key-type*/<InputIter>>,
Allocator>;
template<ranges::input_range R, class Allocator>
multimap(from_range_t, R&&, Allocator) -> multimap</*range-key-type*/<R>,
/*range-mapped-type*/<R>,
less</*range-key-type*/<R>>,
Allocator>;
template<class Key, class T, class Allocator>
multimap(initializer_list<pair<Key, T>>, Allocator)
-> multimap<Key, T, less<Key>, Allocator>;
}
缺陷报告
下列更改行为的缺陷报告追溯地应用于以前出版的 C++ 标准。
| 缺陷报告 | 应用于 | 出版时的行为 | 正确行为 |
|---|---|---|---|
| LWG 133 | C++98 | 概要中缺失了 map::get_allocator | 已补充 |