Standard library header <map>

#include <compare>
#include <initializer_list>
 
namespace std {
 // class template 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)));
 
 // erasure for map
 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);
 
 // class template 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)));
 
 // erasure for multimap
 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>>>;
 }
}

namespace std {
 template<class Key,
 class T,
 class Compare = less<Key>,
 class Allocator = allocator<pair<const Key, T>>>
 class map
 {
 public:
 // types
 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 = /* 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>;
 
 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);
 }
 };
 
 // construct/copy/destroy
 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;
 
 // 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;
 
 // element access
 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;
 
 // 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 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);
 
 // observers
 key_compare key_comp() const;
 value_compare value_comp() const;
 
 // map 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-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>;
}

namespace std {
 template<class Key,
 class T,
 class Compare = less<Key>,
 class Allocator = allocator<pair<const Key, T>>>
 class multimap
 {
 public:
 // types
 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 = /* 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 */;
 
 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);
 }
 };
 
 // construct/copy/destroy
 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;
 
 // 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);
 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);
 
 // observers
 key_compare key_comp() const;
 value_compare value_comp() const;
 
 // map 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-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>;
}