Standard library header <flat_set> (C++23)
From cppreference.com
This header is part of the containers library.
Includes | |
(C++20) |
Three-way comparison operator support |
(C++11) |
std::initializer_list class template |
Classes | |
(C++23) |
adapts a container to provide a collection of unique keys, sorted by keys (class template) |
(C++23) |
adapts a container to provide a collection of keys, sorted by keys (class template) |
| specializes the std::uses_allocator type trait (class template specialization) | |
| specializes the std::uses_allocator type trait (class template specialization) | |
Functions | |
(C++23) |
erases all elements satisfying specific criteria (function template) |
(C++23) |
erases all elements satisfying specific criteria (function template) |
Tags | |
(C++23) |
indicates that elements of a range are sorted and unique (tag) |
| indicates that elements of a range are sorted (uniqueness is not required) (tag) | |
Synopsis
#include <compare>
#include <initializer_list>
namespace std {
// class template flat_set
template<class Key, class Compare = less<Key>, class KeyContainer = vector<Key>>
class flat_set;
struct sorted_unique_t
{
explicit sorted_unique_t() = default;
};
inline constexpr sorted_unique_t sorted_unique{};
template<class Key, class Compare, class KeyContainer, class Allocator>
struct uses_allocator<flat_set<Key, Compare, KeyContainer>, Allocator>;
// erasure for flat_set
template<class Key, class Compare, class KeyContainer, class Predicate>
typename flat_set<Key, Compare, KeyContainer>::size_type erase_if(
flat_set<Key, Compare, KeyContainer>& c,
Predicate pred);
// class template flat_multiset
template<class Key, class Compare = less<Key>, class KeyContainer = vector<Key>>
class flat_multiset;
struct sorted_equivalent_t
{
explicit sorted_equivalent_t() = default;
};
inline constexpr sorted_equivalent_t sorted_equivalent{};
template<class Key, class Compare, class KeyContainer, class Allocator>
struct uses_allocator<flat_multiset<Key, Compare, KeyContainer>, Allocator>;
// erasure for flat_multiset
template<class Key, class Compare, class KeyContainer, class Predicate>
typename flat_multiset<Key, Compare, KeyContainer>::size_type erase_if(
flat_multiset<Key, Compare, KeyContainer>& c,
Predicate pred);
}
Class template std::flat_set
namespace std {
template<class Key, class Compare = less<Key>, class KeyContainer = vector<Key>>
class flat_set
{
public:
// types
using key_type = Key;
using value_type = Key;
using key_compare = Compare;
using value_compare = Compare;
using reference = value_type&;
using const_reference = const value_type&;
using size_type = typename KeyContainer::size_type;
using difference_type = typename KeyContainer::difference_type;
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 container_type = KeyContainer;
// constructors
flat_set()
: flat_set(key_compare())
{
}
explicit flat_set(const key_compare& comp)
: /*c*/()
, /*compare*/(comp)
{
}
explicit flat_set(container_type cont, const key_compare& comp = key_compare());
flat_set(sorted_unique_t,
container_type cont,
const key_compare& comp = key_compare())
: /*c*/(std::move(cont))
, /*compare*/(comp)
{
}
template<class InputIter>
flat_set(InputIter first, InputIter last, const key_compare& comp = key_compare())
: /*c*/()
, /*compare*/(comp)
{
insert(first, last);
}
template<class InputIter>
flat_set(sorted_unique_t,
InputIter first,
InputIter last,
const key_compare& comp = key_compare())
: /*c*/(first, last)
, /*compare*/(comp)
{
}
template<container-compatible-range<value_type> R>
flat_set(from_range_t fr, R&& rg)
: flat_set(fr, std::forward<R>(rg), key_compare())
{
}
template<container-compatible-range<value_type> R>
flat_set(from_range_t, R&& rg, const key_compare& comp)
: flat_set(comp)
{
insert_range(std::forward<R>(rg));
}
flat_set(initializer_list<value_type> il, const key_compare& comp = key_compare())
: flat_set(il.begin(), il.end(), comp)
{
}
flat_set(sorted_unique_t s,
initializer_list<value_type> il,
const key_compare& comp = key_compare())
: flat_set(s, il.begin(), il.end(), comp)
{
}
// constructors with allocators
template<class Alloc>
explicit flat_set(const Alloc& a);
template<class Alloc>
flat_set(const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_set(const container_type& cont, const Alloc& a);
template<class Alloc>
flat_set(const container_type& cont, const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_set(sorted_unique_t, const container_type& cont, const Alloc& a);
template<class Alloc>
flat_set(sorted_unique_t,
const container_type& cont,
const key_compare& comp,
const Alloc& a);
template<class Alloc>
flat_set(const flat_set&, const Alloc& a);
template<class Alloc>
flat_set(flat_set&&, const Alloc& a);
template<class InputIter, class Alloc>
flat_set(InputIter first, InputIter last, const Alloc& a);
template<class InputIter, class Alloc>
flat_set(InputIter first, InputIter last, const key_compare& comp, const Alloc& a);
template<class InputIter, class Alloc>
flat_set(sorted_unique_t, InputIter first, InputIter last, const Alloc& a);
template<class InputIter, class Alloc>
flat_set(sorted_unique_t,
InputIter first,
InputIter last,
const key_compare& comp,
const Alloc& a);
template<container-compatible-range<value_type> R, class Alloc>
flat_set(from_range_t, R&& rg, const Alloc& a);
template<container-compatible-range<value_type> R, class Alloc>
flat_set(from_range_t, R&& rg, const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_set(initializer_list<value_type> il, const Alloc& a);
template<class Alloc>
flat_set(initializer_list<value_type> il, const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_set(sorted_unique_t, initializer_list<value_type> il, const Alloc& a);
template<class Alloc>
flat_set(sorted_unique_t,
initializer_list<value_type> il,
const key_compare& comp,
const Alloc& a);
flat_set& operator=(initializer_list<value_type>);
// 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
[[nodiscard]] 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) { return emplace(x); }
pair<iterator, bool> insert(value_type&& x) { return emplace(std::move(x)); }
template<class K>
pair<iterator, bool> insert(K&& x);
iterator insert(const_iterator position, const value_type& x)
{
return emplace_hint(position, x);
}
iterator insert(const_iterator position, value_type&& x)
{
return emplace_hint(position, std::move(x));
}
template<class K>
iterator insert(const_iterator hint, K&& x);
template<class InputIter>
void insert(InputIter first, InputIter last);
template<class InputIter>
void insert(sorted_unique_t, InputIter first, InputIter last);
template<container-compatible-range<value_type> R>
void insert_range(R&& rg);
void insert(initializer_list<value_type> il) { insert(il.begin(), il.end()); }
void insert(sorted_unique_t s, initializer_list<value_type> il)
{
insert(s, il.begin(), il.end());
}
container_type extract() &&;
void replace(container_type&&);
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(flat_set& y) noexcept;
void clear() noexcept;
// 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;
friend bool operator==(const flat_set& x, const flat_set& y);
friend /*synth-three-way-result*/<value_type> operator<=>(const flat_set& x,
const flat_set& y);
friend void swap(flat_set& x, flat_set& y) noexcept { x.swap(y); }
private:
container_type /*c*/; // exposition only
key_compare /*compare*/; // exposition only
};
template<class KeyContainer, class Compare = less<typename KeyContainer::value_type>>
flat_set(KeyContainer, Compare = Compare())
-> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Allocator>
flat_set(KeyContainer, Allocator) -> flat_set<typename KeyContainer::value_type,
less<typename KeyContainer::value_type>,
KeyContainer>;
template<class KeyContainer, class Compare, class Allocator>
flat_set(KeyContainer, Compare, Allocator)
-> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Compare = less<typename KeyContainer::value_type>>
flat_set(sorted_unique_t, KeyContainer, Compare = Compare())
-> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Allocator>
flat_set(sorted_unique_t, KeyContainer, Allocator)
-> flat_set<typename KeyContainer::value_type,
less<typename KeyContainer::value_type>,
KeyContainer>;
template<class KeyContainer, class Compare, class Allocator>
flat_set(sorted_unique_t, KeyContainer, Compare, Allocator)
-> flat_set<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class InputIter, class Compare = less</*iter-value-type*/<InputIter>>>
flat_set(InputIter, InputIter, Compare = Compare())
-> flat_set</*iter-value-type*/<InputIter>, Compare>;
template<class InputIter, class Compare = less</*iter-value-type*/<InputIter>>>
flat_set(sorted_unique_t, InputIter, InputIter, Compare = Compare())
-> flat_set</*iter-value-type*/<InputIter>, Compare>;
template<ranges::input_range R,
class Compare = less<ranges::range_value_t<R>>,
class Allocator = allocator<ranges::range_value_t<R>>>
flat_set(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
-> flat_set<ranges::range_value_t<R>,
Compare,
vector<ranges::range_value_t<R>,
/*alloc-rebind*/<Allocator, ranges::range_value_t<R>>>>;
template<ranges::input_range R, class Allocator>
flat_set(from_range_t, R&&, Allocator)
-> flat_set<ranges::range_value_t<R>,
less<ranges::range_value_t<R>>,
vector<ranges::range_value_t<R>,
/*alloc-rebind*/<Allocator, ranges::range_value_t<R>>>>;
template<class Key, class Compare = less<Key>>
flat_set(initializer_list<Key>, Compare = Compare()) -> flat_set<Key, Compare>;
template<class Key, class Compare = less<Key>>
flat_set(sorted_unique_t, initializer_list<Key>, Compare = Compare())
-> flat_set<Key, Compare>;
template<class Key, class Compare, class KeyContainer, class Allocator>
struct uses_allocator<flat_set<Key, Compare, KeyContainer>, Allocator>
: bool_constant<uses_allocator_v<KeyContainer, Allocator>>
{};
}
Class template std::flat_multiset
namespace std {
template<class Key, class Compare = less<Key>, class KeyContainer = vector<Key>>
class flat_multiset
{
public:
// types
using key_type = Key;
using value_type = Key;
using key_compare = Compare;
using value_compare = Compare;
using reference = value_type&;
using const_reference = const value_type&;
using size_type = typename KeyContainer::size_type;
using difference_type = typename KeyContainer::difference_type;
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 container_type = KeyContainer;
// constructors
flat_multiset()
: flat_multiset(key_compare())
{
}
explicit flat_multiset(const key_compare& comp)
: /*c*/()
, /*compare*/(comp)
{
}
explicit flat_multiset(container_type cont, const key_compare& comp = key_compare());
flat_multiset(sorted_equivalent_t,
container_type cont,
const key_compare& comp = key_compare())
: /*c*/(std::move(cont))
, /*compare*/(comp)
{
}
template<class InputIter>
flat_multiset(InputIter first,
InputIter last,
const key_compare& comp = key_compare())
: /*c*/()
, /*compare*/(comp)
{
insert(first, last);
}
template<class InputIter>
flat_multiset(sorted_equivalent_t,
InputIter first,
InputIter last,
const key_compare& comp = key_compare())
: /*c*/(first, last)
, /*compare*/(comp)
{
}
template<container-compatible-range<value_type> R>
flat_multiset(from_range_t fr, R&& rg)
: flat_multiset(fr, std::forward<R>(rg), key_compare())
{
}
template<container-compatible-range<value_type> R>
flat_multiset(from_range_t, R&& rg, const key_compare& comp)
: flat_multiset(comp)
{
insert_range(std::forward<R>(rg));
}
flat_multiset(initializer_list<value_type> il,
const key_compare& comp = key_compare())
: flat_multiset(il.begin(), il.end(), comp)
{
}
flat_multiset(sorted_equivalent_t s,
initializer_list<value_type> il,
const key_compare& comp = key_compare())
: flat_multiset(s, il.begin(), il.end(), comp)
{
}
// constructors with allocators
template<class Alloc>
explicit flat_multiset(const Alloc& a);
template<class Alloc>
flat_multiset(const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_multiset(const container_type& cont, const Alloc& a);
template<class Alloc>
flat_multiset(const container_type& cont, const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_multiset(sorted_equivalent_t, const container_type& cont, const Alloc& a);
template<class Alloc>
flat_multiset(sorted_equivalent_t,
const container_type& cont,
const key_compare& comp,
const Alloc& a);
template<class Alloc>
flat_multiset(const flat_multiset&, const Alloc& a);
template<class Alloc>
flat_multiset(flat_multiset&&, const Alloc& a);
template<class InputIter, class Alloc>
flat_multiset(InputIter first, InputIter last, const Alloc& a);
template<class InputIter, class Alloc>
flat_multiset(InputIter first,
InputIter last,
const key_compare& comp,
const Alloc& a);
template<class InputIter, class Alloc>
flat_multiset(sorted_equivalent_t, InputIter first, InputIter last, const Alloc& a);
template<class InputIter, class Alloc>
flat_multiset(sorted_equivalent_t,
InputIter first,
InputIter last,
const key_compare& comp,
const Alloc& a);
template<container-compatible-range<value_type> R, class Alloc>
flat_multiset(from_range_t, R&& rg, const Alloc& a);
template<container-compatible-range<value_type> R, class Alloc>
flat_multiset(from_range_t, R&& rg, const key_compare& comp, const Alloc& a);
template<class Alloc>
flat_multiset(initializer_list<value_type> il, const Alloc& a);
template<class Alloc>
flat_multiset(initializer_list<value_type> il,
const key_compare& comp,
const Alloc& a);
template<class Alloc>
flat_multiset(sorted_equivalent_t, initializer_list<value_type> il, const Alloc& a);
template<class Alloc>
flat_multiset(sorted_equivalent_t,
initializer_list<value_type> il,
const key_compare& comp,
const Alloc& a);
flat_multiset& operator=(initializer_list<value_type>);
// 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
[[nodiscard]] 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) { return emplace(x); }
iterator insert(value_type&& x) { return emplace(std::move(x)); }
iterator insert(const_iterator position, const value_type& x)
{
return emplace_hint(position, x);
}
iterator insert(const_iterator position, value_type&& x)
{
return emplace_hint(position, std::move(x));
}
template<class InputIter>
void insert(InputIter first, InputIter last);
template<class InputIter>
void insert(sorted_equivalent_t, InputIter first, InputIter last);
template<container-compatible-range<value_type> R>
void insert_range(R&& rg);
void insert(initializer_list<value_type> il) { insert(il.begin(), il.end()); }
void insert(sorted_equivalent_t s, initializer_list<value_type> il)
{
insert(s, il.begin(), il.end());
}
container_type extract() &&;
void replace(container_type&&);
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(flat_multiset& y) noexcept;
void clear() noexcept;
// 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;
friend bool operator==(const flat_multiset& x, const flat_multiset& y);
friend /*synth-three-way-result*/<value_type> operator<=>(const flat_multiset& x,
const flat_multiset& y);
friend void swap(flat_multiset& x, flat_multiset& y) noexcept { x.swap(y); }
private:
container_type /*c*/; // exposition only
key_compare /*compare*/; // exposition only
};
template<class KeyContainer, class Compare = less<typename KeyContainer::value_type>>
flat_multiset(KeyContainer, Compare = Compare())
-> flat_multiset<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Allocator>
flat_multiset(KeyContainer, Allocator)
-> flat_multiset<typename KeyContainer::value_type,
less<typename KeyContainer::value_type>,
KeyContainer>;
template<class KeyContainer, class Compare, class Allocator>
flat_multiset(KeyContainer, Compare, Allocator)
-> flat_multiset<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Compare = less<typename KeyContainer::value_type>>
flat_multiset(sorted_equivalent_t, KeyContainer, Compare = Compare())
-> flat_multiset<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class KeyContainer, class Allocator>
flat_multiset(sorted_equivalent_t, KeyContainer, Allocator)
-> flat_multiset<typename KeyContainer::value_type,
less<typename KeyContainer::value_type>,
KeyContainer>;
template<class KeyContainer, class Compare, class Allocator>
flat_multiset(sorted_equivalent_t, KeyContainer, Compare, Allocator)
-> flat_multiset<typename KeyContainer::value_type, Compare, KeyContainer>;
template<class InputIter, class Compare = less</*iter-value-type*/<InputIter>>>
flat_multiset(InputIter, InputIter, Compare = Compare())
-> flat_multiset</*iter-value-type*/<InputIter>, Compare>;
template<class InputIter, class Compare = less</*iter-value-type*/<InputIter>>>
flat_multiset(sorted_equivalent_t, InputIter, InputIter, Compare = Compare())
-> flat_multiset</*iter-value-type*/<InputIter>, Compare>;
template<ranges::input_range R,
class Compare = less<ranges::range_value_t<R>>,
class Allocator = allocator<ranges::range_value_t<R>>>
flat_multiset(from_range_t, R&&, Compare = Compare(), Allocator = Allocator())
-> flat_multiset<ranges::range_value_t<R>,
Compare,
vector<ranges::range_value_t<R>,
/*alloc-rebind*/<Allocator, ranges::range_value_t<R>>>>;
template<ranges::input_range R, class Allocator>
flat_multiset(from_range_t, R&&, Allocator)
-> flat_multiset<ranges::range_value_t<R>,
less<ranges::range_value_t<R>>,
vector<ranges::range_value_t<R>,
/*alloc-rebind*/<Allocator, ranges::range_value_t<R>>>>;
template<class Key, class Compare = less<Key>>
flat_multiset(initializer_list<Key>, Compare = Compare())
-> flat_multiset<Key, Compare>;
template<class Key, class Compare = less<Key>>
flat_multiset(sorted_equivalent_t, initializer_list<Key>, Compare = Compare())
-> flat_multiset<Key, Compare>;
template<class Key, class Compare, class KeyContainer, class Allocator>
struct uses_allocator<flat_multiset<Key, Compare, KeyContainer>, Allocator>
: bool_constant<uses_allocator_v<KeyContainer, Allocator>>
{};
}
References
- C++23 standard (ISO/IEC 14882:2024):
- 24.6.5 Header
<flat_set>synopsis [flat.set.syn]
- 24.6.5 Header
- 24.6.11.2 Definition [flat.set.defn]
- 24.6.12.2 Definition [flat.multiset.defn]