std::list - Man Page

typedef _Alloc allocator_type
typedef _List_const_iterator< _Tp > const_iterator
typedef _Tp_alloc_traits::const_pointer const_pointer
typedef _Tp_alloc_traits::const_reference const_reference
typedef std::reverse_iterator< const_iterator > const_reverse_iterator
typedef ptrdiff_t difference_type
typedef _List_iterator< _Tp > iterator
typedef _Tp_alloc_traits::pointer pointer
typedef _Tp_alloc_traits::reference reference
typedef std::reverse_iterator< iterator > reverse_iterator
typedef size_t size_type
typedef _Tp value_type

list ()=default
Creates a list with no elements.
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> list (_InputIterator __first, _InputIterator __last, const allocator_type &__a=allocator_type())
Builds a list from a range.
list (const allocator_type &__a) noexcept
Creates a list with no elements.
list (const list &__x)
List copy constructor.
list (const list &__x, const __type_identity_t< allocator_type > &__a)
list (initializer_list< value_type > __l, const allocator_type &__a=allocator_type())
Builds a list from an initializer_list.
list (list &&)=default
List move constructor.
list (list &&__x, const __type_identity_t< allocator_type > &__a) noexcept(_Node_alloc_traits::_S_always_equal())
list (size_type __n, const allocator_type &__a=allocator_type())
Creates a list with default constructed elements.
list (size_type __n, const value_type &__value, const allocator_type &__a=allocator_type())
Creates a list with copies of an exemplar element.
~list ()=default
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> void assign (_InputIterator __first, _InputIterator __last)
Assigns a range to a list.
void assign (initializer_list< value_type > __l)
Assigns an initializer_list to a list.
void assign (size_type __n, const value_type &__val)
Assigns a given value to a list.
const_reference back () const noexcept
reference back () noexcept
const_iterator begin () const noexcept
iterator begin () noexcept
const_iterator cbegin () const noexcept
const_iterator cend () const noexcept
void clear () noexcept
const_reverse_iterator crbegin () const noexcept
const_reverse_iterator crend () const noexcept
template<typename... _Args> iterator emplace (const_iterator __position, _Args &&... __args)
Constructs object in list before specified iterator.
template<typename... _Args> reference emplace_back (_Args &&... __args)
template<typename... _Args> reference emplace_front (_Args &&... __args)
bool empty () const noexcept
const_iterator end () const noexcept
iterator end () noexcept
iterator erase (const_iterator __first, const_iterator __last) noexcept
Remove a range of elements.
iterator erase (const_iterator __position) noexcept
Remove element at given position.
const_reference front () const noexcept
reference front () noexcept
allocator_type get_allocator () const noexcept
Get a copy of the memory allocation object.
iterator insert (const_iterator __p, initializer_list< value_type > __l)
Inserts the contents of an initializer_list into list before specified const_iterator.
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> iterator insert (const_iterator __position, _InputIterator __first, _InputIterator __last)
Inserts a range into the list.
iterator insert (const_iterator __position, const value_type &__x)
Inserts given value into list before specified iterator.
iterator insert (const_iterator __position, size_type __n, const value_type &__x)
Inserts a number of copies of given data into the list.
iterator insert (const_iterator __position, value_type &&__x)
Inserts given rvalue into list before specified iterator.
size_type max_size () const noexcept
void merge (list &&__x)
Merge sorted lists.
template<typename _StrictWeakOrdering > void merge (list &&__x, _StrictWeakOrdering __comp)
Merge sorted lists according to comparison function.
void merge (list &__x)
template<typename _StrictWeakOrdering > void merge (list &__x, _StrictWeakOrdering __comp)
list & operator= (const list &__x)
List assignment operator.
list & operator= (initializer_list< value_type > __l)
List initializer list assignment operator.
list & operator= (list &&__x) noexcept(_Node_alloc_traits::_S_nothrow_move())
List move assignment operator.
void pop_back () noexcept
Removes last element.
void pop_front () noexcept
Removes first element.
void push_back (const value_type &__x)
Add data to the end of the list.
void push_back (value_type &&__x)
void push_front (const value_type &__x)
Add data to the front of the list.
void push_front (value_type &&__x)
const_reverse_iterator rbegin () const noexcept
reverse_iterator rbegin () noexcept
__remove_return_type remove (const _Tp &__value)
Remove all elements equal to value.
template<typename _Predicate > __remove_return_type remove_if (_Predicate)
Remove all elements satisfying a predicate.
const_reverse_iterator rend () const noexcept
reverse_iterator rend () noexcept
void resize (size_type __new_size)
Resizes the list to the specified number of elements.
void resize (size_type __new_size, const value_type &__x)
Resizes the list to the specified number of elements.
void reverse () noexcept
Reverse the elements in list.
size_type size () const noexcept
void sort ()
Sort the elements.
template<typename _StrictWeakOrdering > void sort (_StrictWeakOrdering)
Sort the elements according to comparison function.
void splice (const_iterator __position, list &&__x) noexcept
Insert contents of another list.
void splice (const_iterator __position, list &&__x, const_iterator __first, const_iterator __last) noexcept
Insert range from another list.
void splice (const_iterator __position, list &&__x, const_iterator __i) noexcept
Insert element from another list.
void splice (const_iterator __position, list &__x) noexcept
void splice (const_iterator __position, list &__x, const_iterator __first, const_iterator __last) noexcept
Insert range from another list.
void splice (const_iterator __position, list &__x, const_iterator __i) noexcept
Insert element from another list.
void swap (list &__x) noexcept
Swaps data with another list.
__remove_return_type unique ()
Remove consecutive duplicate elements.
template<typename _BinaryPredicate > __remove_return_type unique (_BinaryPredicate)
Remove consecutive elements satisfying a predicate.

typedef _List_node< _Tp > _Node

template<typename _InputIterator > void _M_assign_dispatch (_InputIterator __first, _InputIterator __last, __false_type)
template<typename _Integer > void _M_assign_dispatch (_Integer __n, _Integer __val, __true_type)
void _M_check_equal_allocators (const list &__x) noexcept
void _M_clear () noexcept
template<typename... _Args> _Node * _M_create_node (_Args &&... __args)
void _M_dec_size (size_t __n)
void _M_default_append (size_type __n)
void _M_default_initialize (size_type __n)
size_t _M_distance (const __detail::_List_node_base *__first, const __detail::_List_node_base *__last) const
void _M_erase (iterator __position) noexcept
void _M_fill_assign (size_type __n, const value_type &__val)
void _M_fill_initialize (size_type __n, const value_type &__x)
_Node_alloc_traits::pointer _M_get_node ()
const _Node_alloc_type & _M_get_Node_allocator () const noexcept
_Node_alloc_type & _M_get_Node_allocator () noexcept
size_t _M_get_size () const
void _M_inc_size (size_t __n)
void _M_init () noexcept
template<typename _InputIterator > void _M_initialize_dispatch (_InputIterator __first, _InputIterator __last, __false_type)
template<typename _Integer > void _M_initialize_dispatch (_Integer __n, _Integer __x, __true_type)
template<typename... _Args> void _M_insert (iterator __position, _Args &&... __args)
void _M_move_assign (list &&__x, false_type)
void _M_move_assign (list &&__x, true_type) noexcept
void _M_move_nodes (_List_base &&__x)
size_t _M_node_count () const
void _M_put_node (typename _Node_alloc_traits::pointer __p) noexcept
const_iterator _M_resize_pos (size_type &__new_size) const
void _M_set_size (size_t __n)
void _M_transfer (iterator __position, iterator __first, iterator __last)

static size_t _S_distance (const __detail::_List_node_base *__first, const __detail::_List_node_base *__last)
static size_t _S_distance (const_iterator __first, const_iterator __last)

_List_impl _M_impl

class std::list< _Tp, _Alloc >"A standard container with linear time access to elements, and fixed time insertion/deletion at any point in the sequence.

Template Parameters

Meets the requirements of a container, a reversible container, and a sequence, including the optional sequence requirements with the exception of at and operator[].

This is a doubly linked list. Traversal up and down the list requires linear time, but adding and removing elements (or nodes) is done in constant time, regardless of where the change takes place. Unlike std::vector and std::deque, random-access iterators are not provided, so subscripting ( [] ) access is not allowed. For algorithms which only need sequential access, this lack makes no difference.

Also unlike the other standard containers, std::list provides specialized algorithms unique to linked lists, such as splicing, sorting, and in-place reversal.

A couple points on memory allocation for list<Tp>:

First, we never actually allocate a Tp, we allocate List_node<Tp>'s and trust [20.1.5]/4 to DTRT. This is to ensure that after elements from list<X,Alloc1> are spliced into list<X,Alloc2>, destroying the memory of the second list is a valid operation, i.e., Alloc1 giveth and Alloc2 taketh away.

Second, a list conceptually represented as

A <---> B <---> C <---> D

is actually circular; a link exists between A and D. The list class holds (as its only data member) a private list::iterator pointing to D, not to A! To get to the head of the list, we start at the tail and move forward by one. When this member iterator's next/previous pointers refer to itself, the list is empty.

Creates a list with no elements.

Creates a list with no elements.

Parameters

Creates a list with default constructed elements.

Parameters

This constructor fills the list with __n default constructed elements.

Creates a list with copies of an exemplar element.

Parameters

This constructor fills the list with __n copies of __value.

List copy constructor.

Parameters

The newly-created list uses a copy of the allocation object used by __x (unless the allocator traits dictate a different object).

References std::list< _Tp, _Alloc >::begin(), and std::list< _Tp, _Alloc >::end().

List move constructor. The newly-created list contains the exact contents of the moved instance. The contents of the moved instance are a valid, but unspecified list.

Builds a list from an initializer_list.

Parameters

Create a list consisting of copies of the elements in the initializer_list __l. This is linear in __l.size().

Builds a list from a range.

Parameters

Create a list consisting of copies of the elements from [__first,__last). This is linear in N (where N is distance(__first,__last)).

No explicit dtor needed as the _Base dtor takes care of things. The _Base dtor only erases the elements, and note that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Parameters

Allocates space for a new node and constructs a copy of __args in it.

References std::forward().

Assigns a range to a list.

Parameters

This function fills a list with copies of the elements in the range [__first,__last).

Note that the assignment completely changes the list and that the resulting list's size is the same as the number of elements assigned.

Assigns an initializer_list to a list.

Parameters

Replace the contents of the list with copies of the elements in the initializer_list __l. This is linear in __l.size().

Assigns a given value to a list.

Parameters

This function fills a list with __n copies of the given value. Note that the assignment completely changes the list and that the resulting list's size is the same as the number of elements assigned.

Referenced by std::list< _Tp, _Alloc >::operator=().

Returns a read-only (constant) reference to the data at the last element of the list.

References std::list< _Tp, _Alloc >::end().

Returns a read/write reference to the data at the last element of the list.

References std::list< _Tp, _Alloc >::end().

Returns a read-only (constant) iterator that points to the first element in the list. Iteration is done in ordinary element order.

Returns a read/write iterator that points to the first element in the list. Iteration is done in ordinary element order.

Referenced by std::list< _Tp, _Alloc >::list(), std::list< _Tp, _Alloc >::crend(), std::list< _Tp, _Alloc >::front(), std::list< _Tp, _Alloc >::front(), std::list< _Tp, _Alloc >::insert(), std::list< _Tp, _Alloc >::insert(), std::list< _Tp, _Alloc >::merge(), std::list< _Tp, _Alloc >::merge(), std::operator<=>(), std::list< _Tp, _Alloc >::operator=(), std::list< _Tp, _Alloc >::pop_front(), std::list< _Tp, _Alloc >::push_front(), std::list< _Tp, _Alloc >::remove(), std::list< _Tp, _Alloc >::remove_if(), std::list< _Tp, _Alloc >::rend(), std::list< _Tp, _Alloc >::rend(), std::list< _Tp, _Alloc >::splice(), std::list< _Tp, _Alloc >::unique(), and std::list< _Tp, _Alloc >::unique().

Returns a read-only (constant) iterator that points to the first element in the list. Iteration is done in ordinary element order.

Returns a read-only (constant) iterator that points one past the last element in the list. Iteration is done in ordinary element order.

Erases all the elements. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Returns a read-only (constant) reverse iterator that points to the last element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::end().

Returns a read-only (constant) reverse iterator that points to one before the first element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::begin().

Constructs object in list before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert an object of type T constructed with T(std::forward<Args>(args)...) before the specified location. Due to the nature of a list this operation can be done in constant time, and does not invalidate iterators and references.

References std::forward().

Referenced by std::list< _Tp, _Alloc >::insert().

Returns true if the list is empty. (Thus begin() would equal end().)

Referenced by std::list< _Tp, _Alloc >::insert(), and std::list< _Tp, _Alloc >::splice().

Returns a read-only (constant) iterator that points one past the last element in the list. Iteration is done in ordinary element order.

Returns a read/write iterator that points one past the last element in the list. Iteration is done in ordinary element order.

Referenced by std::list< _Tp, _Alloc >::list(), std::list< _Tp, _Alloc >::back(), std::list< _Tp, _Alloc >::back(), std::list< _Tp, _Alloc >::crbegin(), std::list< _Tp, _Alloc >::merge(), std::list< _Tp, _Alloc >::merge(), std::operator<=>(), std::list< _Tp, _Alloc >::operator=(), std::list< _Tp, _Alloc >::push_back(), std::list< _Tp, _Alloc >::rbegin(), std::list< _Tp, _Alloc >::rbegin(), and std::list< _Tp, _Alloc >::splice().

Remove a range of elements.

Parameters

Returns

An iterator pointing to the element pointed to by last prior to erasing (or end()).

This function will erase the elements in the range [first,last) and shorten the list accordingly.

This operation is linear time in the size of the range and only invalidates iterators/references to the element being removed. The user is also cautioned that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::list< _Tp, _Alloc >::erase().

Remove element at given position.

Parameters

Returns

An iterator pointing to the next element (or end()).

This function will erase the element at the given position and thus shorten the list by one.

Due to the nature of a list this operation can be done in constant time, and only invalidates iterators/references to the element being removed. The user is also cautioned that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Referenced by std::list< _Tp, _Alloc >::erase().

Returns a read-only (constant) reference to the data at the first element of the list.

References std::list< _Tp, _Alloc >::begin().

Returns a read/write reference to the data at the first element of the list.

References std::list< _Tp, _Alloc >::begin().

Get a copy of the memory allocation object.

Inserts the contents of an initializer_list into list before specified const_iterator.

Parameters

Returns

An iterator pointing to the first element inserted (or __position).

This function will insert copies of the data in the initializer_list l into the list before the location specified by p.

This operation is linear in the number of elements inserted and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::insert().

Inserts a range into the list.

Parameters

Returns

An iterator pointing to the first element inserted (or __position).

This function will insert copies of the data in the range [first,last) into the list before the location specified by position.

This operation is linear in the number of elements inserted and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::begin(), and std::list< _Tp, _Alloc >::empty().

Inserts given value into list before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert a copy of the given value before the specified location. Due to the nature of a list this operation can be done in constant time, and does not invalidate iterators and references.

Referenced by std::list< _Tp, _Alloc >::insert().

Inserts a number of copies of given data into the list.

Parameters

Returns

An iterator pointing to the first element inserted (or __position).

This function will insert a specified number of copies of the given data before the location specified by position.

This operation is linear in the number of elements inserted and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::begin().

Inserts given rvalue into list before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert a copy of the given rvalue before the specified location. Due to the nature of a list this operation can be done in constant time, and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::emplace(), and std::move().

Returns the size() of the largest possible list.

References std::allocator_traits< _Alloc >::max_size().

Merge sorted lists.

Parameters

Assumes that both __x and this list are sorted according to operator<(). Merges elements of __x into this list in sorted order, leaving __x empty when complete. Elements in this list precede elements in __x that are equal.

References std::__addressof(), std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), and std::list< _Tp, _Alloc >::end().

Merge sorted lists according to comparison function.

Template Parameters

Parameters

Assumes that both __x and this list are sorted according to StrictWeakOrdering. Merges elements of __x into this list in sorted order, leaving __x empty when complete. Elements in this list precede elements in __x that are equivalent according to StrictWeakOrdering().

References std::__addressof(), std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), and std::list< _Tp, _Alloc >::end().

List assignment operator.

Parameters

All the elements of __x are copied.

Whether the allocator is copied depends on the allocator traits.

References std::__addressof(), std::list< _Tp, _Alloc >::begin(), and std::list< _Tp, _Alloc >::end().

List initializer list assignment operator.

Parameters

Replace the contents of the list with copies of the elements in the initializer_list __l. This is linear in l.size().

References std::list< _Tp, _Alloc >::assign().

List move assignment operator.

Parameters

The contents of __x are moved into this list (without copying).

Afterwards __x is a valid, but unspecified list

Whether the allocator is moved depends on the allocator traits.

References std::move().

Removes last element. This is a typical stack operation. It shrinks the list by one. Due to the nature of a list this operation can be done in constant time, and only invalidates iterators/references to the element being removed.

Note that no data is returned, and if the last element's data is needed, it should be retrieved before pop_back() is called.

Removes first element. This is a typical stack operation. It shrinks the list by one. Due to the nature of a list this operation can be done in constant time, and only invalidates iterators/references to the element being removed.

Note that no data is returned, and if the first element's data is needed, it should be retrieved before pop_front() is called.

References std::list< _Tp, _Alloc >::begin().

Add data to the end of the list.

Parameters

This is a typical stack operation. The function creates an element at the end of the list and assigns the given data to it. Due to the nature of a list this operation can be done in constant time, and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::end().

Add data to the front of the list.

Parameters

This is a typical stack operation. The function creates an element at the front of the list and assigns the given data to it. Due to the nature of a list this operation can be done in constant time, and does not invalidate iterators and references.

References std::list< _Tp, _Alloc >::begin().

Returns a read-only (constant) reverse iterator that points to the last element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::end().

Returns a read/write reverse iterator that points to the last element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::end().

Remove all elements equal to value.

Parameters

Removes every element in the list equal to value. Remaining elements stay in list order. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), std::list< _Tp, _Alloc >::size(), and std::list< _Tp, _Alloc >::splice().

Remove all elements satisfying a predicate.

Template Parameters

Removes every element in the list for which the predicate returns true. Remaining elements stay in list order. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), std::list< _Tp, _Alloc >::size(), and std::list< _Tp, _Alloc >::splice().

Returns a read-only (constant) reverse iterator that points to one before the first element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::begin().

Returns a read/write reverse iterator that points to one before the first element in the list. Iteration is done in reverse element order.

References std::list< _Tp, _Alloc >::begin().

Resizes the list to the specified number of elements.

Parameters

This function will resize the list to the specified number of elements. If the number is smaller than the list's current size the list is truncated, otherwise default constructed elements are appended.

References std::end().

Resizes the list to the specified number of elements.

Parameters

This function will resize the list to the specified number of elements. If the number is smaller than the list's current size the list is truncated, otherwise the list is extended and new elements are populated with given data.

References std::end().

Reverse the elements in list. Reverse the order of elements in the list in linear time.

Returns the number of elements in the list.

Referenced by std::operator<=>(), std::list< _Tp, _Alloc >::remove(), std::list< _Tp, _Alloc >::remove_if(), std::list< _Tp, _Alloc >::unique(), and std::list< _Tp, _Alloc >::unique().

Sort the elements. Sorts the elements of this list in NlogN time. Equivalent elements remain in list order.

References std::begin(), std::empty(), and std::end().

Sort the elements according to comparison function. Sorts the elements of this list in NlogN time. Equivalent elements remain in list order.

References std::begin(), std::empty(), and std::end().

Insert contents of another list.

Parameters

The elements of __x are inserted in constant time in front of the element referenced by __position. __x becomes an empty list.

Requires this != __x.

References std::list< _Tp, _Alloc >::begin(), std::list< _Tp, _Alloc >::empty(), and std::list< _Tp, _Alloc >::end().

Referenced by std::list< _Tp, _Alloc >::remove(), std::list< _Tp, _Alloc >::remove_if(), std::list< _Tp, _Alloc >::splice(), std::list< _Tp, _Alloc >::splice(), std::list< _Tp, _Alloc >::unique(), and std::list< _Tp, _Alloc >::unique().

Insert range from another list.

Parameters

Removes elements in the range [__first,__last) and inserts them before __position in constant time.

Undefined if __position is in [__first,__last).

References std::__addressof().

Insert element from another list.

Parameters

Removes the element in list __x referenced by __i and inserts it into the current list before __position.

References std::__addressof().

Insert range from another list.

Parameters

Removes elements in the range [__first,__last) and inserts them before __position in constant time.

Undefined if __position is in [__first,__last).

References std::move(), and std::list< _Tp, _Alloc >::splice().

Insert element from another list.

Parameters

Removes the element in list __x referenced by __i and inserts it into the current list before __position.

References std::move(), and std::list< _Tp, _Alloc >::splice().

Swaps data with another list.

Parameters

This exchanges the elements between two lists in constant time. Note that the global std::swap() function is specialized such that std::swap(l1,l2) will feed to this function.

Whether the allocators are swapped depends on the allocator traits.

Remove consecutive duplicate elements. For each consecutive set of elements with the same value, remove all but the first one. Remaining elements stay in list order. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), std::list< _Tp, _Alloc >::size(), and std::list< _Tp, _Alloc >::splice().

Remove consecutive elements satisfying a predicate.

Template Parameters

For each consecutive set of elements [first,last) that satisfy predicate(first,i) where i is an iterator in [first,last), remove all but the first one. Remaining elements stay in list order. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::begin(), std::list< _Tp, _Alloc >::begin(), std::end(), std::list< _Tp, _Alloc >::size(), and std::list< _Tp, _Alloc >::splice().