[list.overview]

# 23 Containers library [[containers]](./#containers)

## 23.3 Sequence containers [[sequences]](sequences#list.overview)

### 23.3.11 Class template list [[list]](list#overview)

#### 23.3.11.1 Overview [list.overview]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L9016)

Alist is a sequence container that supports
bidirectional iterators and allows constant time insert and erase
operations anywhere within the sequence, with storage management handled
automatically[.](#1.sentence-1)

Unlike [vectors](vector "23.3.13 Class template vector [vector]") and [deques](deque "23.3.5 Class template deque [deque]"),
fast random access to list elements is not supported, but many
algorithms only need sequential access anyway[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L9027)

A list meets all of the requirements
of a container ([[container.reqmts]](container.reqmts "23.2.2.2 Container requirements")),
of a reversible container ([[container.rev.reqmts]](container.rev.reqmts "23.2.2.3 Reversible container requirements")),
of an allocator-aware container ([[container.alloc.reqmts]](container.alloc.reqmts "23.2.2.5 Allocator-aware containers")), and
of a sequence container,
including most of the optional sequence container
requirements ([[sequence.reqmts]](sequence.reqmts "23.2.4 Sequence containers"))[.](#2.sentence-1)

The exceptions are theoperator[] andat member functions, which are not provided[.](#2.sentence-2)[195](#footnote-195 "These member functions are only provided by containers whose iterators are random access iterators.")

Descriptions are provided here only for operations onlist that are not described in one of these tables
or for operations where there is additional semantic information[.](#2.sentence-3)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L9050)

The types iterator and const_iterator meet
the constexpr iterator requirements[[iterator.requirements.general]](iterator.requirements.general "24.3.1 General")[.](#3.sentence-1)

namespace std {template<class T, class Allocator = allocator<T>>class list {public:// typesusing value_type = T; 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*; // see [[container.requirements]](container.requirements "23.2 Requirements")using difference_type = *implementation-defined*; // see [[container.requirements]](container.requirements "23.2 Requirements")using iterator = *implementation-defined*; // see [[container.requirements]](container.requirements "23.2 Requirements")using const_iterator = *implementation-defined*; // see [[container.requirements]](container.requirements "23.2 Requirements")using reverse_iterator = std::reverse_iterator<iterator>; using const_reverse_iterator = std::reverse_iterator<const_iterator>; // [[list.cons]](list.cons "23.3.11.2 Constructors, copy, and assignment"), construct/copy/destroyconstexpr list() : list(Allocator()) { }constexpr explicit list(const Allocator&); constexpr explicit list(size_type n, const Allocator& = Allocator()); constexpr list(size_type n, const T& value, const Allocator& = Allocator()); template<class InputIterator>constexpr list(InputIterator first, InputIterator last, const Allocator& = Allocator()); template<[*container-compatible-range*](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<T> R>constexpr list(from_range_t, R&& rg, const Allocator& = Allocator()); constexpr list(const list& x); constexpr list(list&& x); constexpr list(const list&, const type_identity_t<Allocator>&); constexpr list(list&&, const type_identity_t<Allocator>&); constexpr list(initializer_list<T>, const Allocator& = Allocator()); constexpr ~list(); constexpr list& operator=(const list& x); constexpr list& operator=(list&& x)noexcept(allocator_traits<Allocator>::is_always_equal::value); constexpr list& operator=(initializer_list<T>); template<class InputIterator>constexpr void assign(InputIterator first, InputIterator last); template<[*container-compatible-range*](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<T> R>constexpr void assign_range(R&& rg); constexpr void assign(size_type n, const T& t); constexpr void assign(initializer_list<T>); constexpr allocator_type get_allocator() const noexcept; // iteratorsconstexpr iterator begin() noexcept; constexpr const_iterator begin() const noexcept; constexpr iterator end() noexcept; constexpr const_iterator end() const noexcept; constexpr reverse_iterator rbegin() noexcept; constexpr const_reverse_iterator rbegin() const noexcept; constexpr reverse_iterator rend() noexcept; constexpr const_reverse_iterator rend() const noexcept; constexpr const_iterator cbegin() const noexcept; constexpr const_iterator cend() const noexcept; constexpr const_reverse_iterator crbegin() const noexcept; constexpr const_reverse_iterator crend() const noexcept; // [[list.capacity]](list.capacity "23.3.11.3 Capacity"), capacityconstexpr bool empty() const noexcept; constexpr size_type size() const noexcept; constexpr size_type max_size() const noexcept; constexpr void resize(size_type sz); constexpr void resize(size_type sz, const T& c); // element accessconstexpr reference front(); constexpr const_reference front() const; constexpr reference back(); constexpr const_reference back() const; // [[list.modifiers]](list.modifiers "23.3.11.4 Modifiers"), modifierstemplate<class... Args> constexpr reference emplace_front(Args&&... args); template<class... Args> constexpr reference emplace_back(Args&&... args); constexpr void push_front(const T& x); constexpr void push_front(T&& x); template<[*container-compatible-range*](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<T> R>constexpr void prepend_range(R&& rg); constexpr void pop_front(); constexpr void push_back(const T& x); constexpr void push_back(T&& x); template<[*container-compatible-range*](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<T> R>constexpr void append_range(R&& rg); constexpr void pop_back(); template<class... Args> constexpr iterator emplace(const_iterator position, Args&&... args); constexpr iterator insert(const_iterator position, const T& x); constexpr iterator insert(const_iterator position, T&& x); constexpr iterator insert(const_iterator position, size_type n, const T& x); template<class InputIterator>constexpr iterator insert(const_iterator position,
 InputIterator first, InputIterator last); template<[*container-compatible-range*](container.intro.reqmts#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]")<T> R>constexpr iterator insert_range(const_iterator position, R&& rg); constexpr iterator insert(const_iterator position, initializer_list<T> il); constexpr iterator erase(const_iterator position); constexpr iterator erase(const_iterator position, const_iterator last); constexpr void swap(list&) noexcept(allocator_traits<Allocator>::is_always_equal::value); constexpr void clear() noexcept; // [[list.ops]](list.ops "23.3.11.5 Operations"), list operationsconstexpr void splice(const_iterator position, list& x); constexpr void splice(const_iterator position, list&& x); constexpr void splice(const_iterator position, list& x, const_iterator i); constexpr void splice(const_iterator position, list&& x, const_iterator i); constexpr void splice(const_iterator position, list& x,
 const_iterator first, const_iterator last); constexpr void splice(const_iterator position, list&& x,
 const_iterator first, const_iterator last); constexpr size_type remove(const T& value); template<class Predicate> constexpr size_type remove_if(Predicate pred); constexpr size_type unique(); template<class BinaryPredicate>constexpr size_type unique(BinaryPredicate binary_pred); constexpr void merge(list& x); constexpr void merge(list&& x); template<class Compare> constexpr void merge(list& x, Compare comp); template<class Compare> constexpr void merge(list&& x, Compare comp); constexpr void sort(); template<class Compare> constexpr void sort(Compare comp); constexpr void reverse() noexcept; }; template<class InputIterator, class Allocator = allocator<*iter-value-type*<InputIterator>>> list(InputIterator, InputIterator, Allocator = Allocator())-> list<*iter-value-type*<InputIterator>, Allocator>; template<ranges::[input_range](range.refinements#concept:input_range "25.4.6 Other range refinements [range.refinements]") R, class Allocator = allocator<ranges::range_value_t<R>>> list(from_range_t, R&&, Allocator = Allocator())-> list<ranges::range_value_t<R>, Allocator>;}

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L9196)

An incomplete type T may be used when instantiating list if the allocator meets the[allocator completeness requirements](allocator.requirements.completeness "16.4.4.6.2 Allocator completeness requirements [allocator.requirements.completeness]")[.](#4.sentence-1)

T shall be complete before any member of the resulting specialization
of list is referenced[.](#4.sentence-2)

[195)](#footnote-195)[195)](#footnoteref-195)

These member functions
are only provided by containers whose iterators
are random access iterators[.](#footnote-195.sentence-1)