std::list - cppreference.com

From cppreference.com

Defined in header

<list>

template<classT,classAllocator=std::allocator<T>>classlist; (1) namespacepmr{template<classT>usinglist=std::list<T,std::pmr::polymorphic_allocator<T>>;} (2) (since C++17)std::list is a container that supports constant time insertion and removal of elements from anywhere in the container. Fast random access is not supported. It is usually implemented as a doubly-linked list. Compared to

std::forward_list

this container provides bidirectional iteration capability while being less space efficient.

Adding, removing and moving the elements within the list or across several lists does not invalidate the iterators or references. An iterator is invalidated only when the corresponding element is deleted.

std::list meets the requirements of

Container

,

AllocatorAwareContainer

,

SequenceContainer

and

ReversibleContainer

.

All member functions of std::list are constexpr: it is possible to create and use std::list objects in the evaluation of a constant expression.

However, defining a constexprstd::list variable is generally an error, because constant evaluation requires any dynamically allocated storage to be released in the same evaluation, which is usually not the case with std::list's initializer.

(since C++26)Template parameters

T - The type of the elements. T must meet the requirements of

CopyConstructible

. T must meet the requirements of

CopyAssignable

if

list::operator=

or

list::assign

is instantiated with T.(until C++11)The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type is a complete type and meets the requirements of

Erasable

, but many member functions impose stricter requirements.(since C++11)
(until C++17)The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type meets the requirements of

Erasable

, but many member functions impose stricter requirements. This container (but not its members) can be instantiated with an

incomplete element type

if the allocator satisfies the

allocator completeness requirements

.

(since C++17)

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Allocator - An allocator that is used to acquire/release memory and to construct/destroy the elements in that memory. The type must meet the requirements of

Allocator

. The behavior is undefined(until C++20)The program is ill-formed(since C++20) if Allocator::value_type is not the same as T.

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Member types

Member functions

(constructor)

constructs the list
(public member function)

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(destructor)

destructs the list
(public member function)

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operator=

assigns values to the container
(public member function)

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assign

assigns values to the container
(public member function)

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assign_range

(C++23)

assigns a range of values to the container
(public member function)

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get_allocator

returns the associated allocator
(public member function)

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Element access

front

access the first element
(public member function)

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back

access the last element
(public member function)

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Iterators

begincbegin

(C++11)

returns an iterator to the beginning
(public member function)

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endcend

(C++11)

returns an iterator to the end
(public member function)

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rbegincrbegin

(C++11)

returns a reverse iterator to the beginning
(public member function)

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rendcrend

(C++11)

returns a reverse iterator to the end
(public member function)

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Capacity

empty

checks whether the container is empty
(public member function)

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size

returns the number of elements
(public member function)

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max_size

returns the maximum possible number of elements
(public member function)

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Modifiers

clear

clears the contents
(public member function)

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insert

inserts elements
(public member function)

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insert_range

(C++23)

inserts a range of elements
(public member function)

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emplace

(C++11)

constructs element in-place
(public member function)

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erase

erases elements
(public member function)

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push_back

adds an element to the end
(public member function)

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emplace_back

(C++11)

constructs an element in-place at the end
(public member function)

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append_range

(C++23)

adds a range of elements to the end
(public member function)

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pop_back

removes the last element
(public member function)

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push_front

inserts an element to the beginning
(public member function)

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emplace_front

(C++11)

constructs an element in-place at the beginning
(public member function)

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prepend_range

(C++23)

adds a range of elements to the beginning
(public member function)

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pop_front

removes the first element
(public member function)

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resize

changes the number of elements stored
(public member function)

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swap

swaps the contents
(public member function)

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Operations

merge

merges two sorted lists
(public member function)

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splice

moves elements from another list
(public member function)

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removeremove_if

removes elements satisfying specific criteria
(public member function)

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reverse

reverses the order of the elements
(public member function)

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unique

removes consecutive duplicate elements
(public member function)

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sort

sorts the elements
(public member function)

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Non-member functions

Notes

Feature-test

macro ValueStdFeature

__cpp_lib_incomplete_container_elements

201505L

(C++17)Minimal incomplete type support

__cpp_lib_containers_ranges

202202L

(C++23)Ranges construction and insertion for containers

__cpp_lib_constexpr_list

202502L

(C++26)Constexpr std::listExample

Run this code

#include<algorithm>#include<iostream>#include<list>intmain(){// Create a list containing integersstd::list<int>l={7,5,16,8};// Add an integer to the front of the listl.push_front(25);// Add an integer to the back of the listl.push_back(13);// Insert an integer before 16 by searchingautoit=std::find(l.begin(),l.end(),16);if(it!=l.end())l.insert(it,42);// Print out the liststd::cout<<"l = { ";for(intn:l)std::cout<<n<<", ";std::cout<<"};\n";}Output:

l = { 25, 7, 5, 42, 16, 8, 13, }; Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior

LWG 230

C++98 T was not required to be

CopyConstructible

(an element of type T might not be able to be constructed) T is also required to
be

CopyConstructible

LWG 276

C++98 T was always required to be

CopyAssignable

only required if

operator=

or

assign

is instantiated with TSee also