Containers library

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

The Containers library is a generic collection of class templates and algorithms that allow programmers to easily implement common data structures like queues, lists and stacks. There are three classes of containers -- sequence containers, associative containers, and unordered associative containers -- each of which is designed to support a different set of operations.

The container manages the storage space that is allocated for its elements and provides member functions to access them, either directly or through iterators (objects with properties similar to pointers).

Most containers have at least several member functions in common, and share functionalities. Which container is the best for the particular application depends not only on the offered functionality, but also on its efficiency for different workloads.

Sequence containers

Sequence containers implement data structures which can be accessed sequentially.

array (since C++11)	static contiguous array (class template)
vector	dynamic contiguous array (class template)
deque	double-ended queue (class template)
forward_list (since C++11)	singly-linked list (class template)
list	doubly-linked list (class template)

Associative containers

Associative containers implement sorted data structures that can be quickly searched (O(log n) complexity).

set	collection of unique keys, sorted by keys (class template)
map	collection of key-value pairs, sorted by keys, keys are unique (class template)
multiset	collection of keys, sorted by keys (class template)
multimap	collection of key-value pairs, sorted by keys (class template)

Unordered associative containers

Unordered associative containers implement unsorted (hashed) data structures that can be quickly searched (O(1) amortized, O(n) worst-case complexity).

unordered_set (since C++11)	collection of unique keys, hashed by keys (class template)
unordered_map (since C++11)	collection of key-value pairs, hashed by keys, keys are unique (class template)
unordered_multiset (since C++11)	collection of keys, hashed by keys (class template)
unordered_multimap (since C++11)	collection of key-value pairs, hashed by keys (class template)

Container adaptors

Container adaptors provide a different interface for sequential containers.

stack	adapts a container to provide stack (LIFO data structure) (class template)
queue	adapts a container to provide queue (FIFO data structure) (class template)
priority_queue	adapts a container to provide priority queue (class template)

Iterator invalidation

Thread safety All container functions can be called concurrently by different threads on different containers. More generally, the C++ standard library functions do not read objects accessible by other threads unless those objects are directly or indirectly accessible via the function arguments, including the this pointer. All const member functions can be called concurrently by different threads on the same container. In addition, the member functions begin(), end(), rbegin(), rend(), front(), back(), data(), find(), lower_bound(), upper_bound(), equal_range(), at(), and, except in associative containers, operator[], behave as const for the purposes of thread safety (that is, they can also be called concurrently by different threads on the same container). More generally, the C++ standard library functions do not modify objects unless those objects are accessible, directly or indirectly, via the function's non-const arguments, including the this pointer. Different elements in the same container can be modified concurrently by different threads, except for the elements of std::vector<bool> (for example, a vector of std::future objects can be receiving values from multiple threads). Iterator operations (e.g. incrementing an iterator) read, but do not modify the underlying container, and may be executed concurrently with operations on other iterators on the same container, with the const member functions, or reads from the elements. Container operations that invalidate any iterators modify the container and cannot be executed concurrently with any operations on existing iterators even if those iterators are not invalidated. Elements of the same container can be modified concurrently with those member functions that are not specified to access these elements. More generally, the C++ standard library functions do not read objects indirectly accessible through their arguments (including other elements of a container) except when required by its specification. In any case, container operations (as well as algorithms, or any other C++ standard library functions) may be parallelized internally as long as this does not change the user-visible results (e.g. std::transform may be parallelized, but not std::for_each which is specified to visit each element of a sequence in order)

(since C++11)

Member function table

	- functions present in C++03
	- functions present since C++11
	- functions present since C++17

		Sequence containers					Associative containers				Unordered associative containers				Container adaptors
Header		<array>	<vector>	<deque>	<forward_list>	<list>	<set>		<map>		<unordered_set>		<unordered_map>		<stack>	<queue>
Container		array	vector	deque	forward_list	list	set	multiset	map	multimap	unordered_set	unordered_multiset	unordered_map	unordered_multimap	stack	queue	priority_queue
	(constructor)	(implicit)	vector	deque	forward_list	list	set	multiset	map	multimap	unordered_set	unordered_multiset	unordered_map	unordered_multimap	stack	queue	priority_queue
	(destructor)	(implicit)	~vector	~deque	~forward_list	~list	~set	~multiset	~map	~multimap	~unordered_set	~unordered_multiset	~unordered_map	~unordered_multimap	~stack	~queue	~priority_queue
	operator=	(implicit)	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=	operator=
	assign		assign	assign	assign	assign
Iterators	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin	begin cbegin
	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend	end cend
	rbegin crbegin	rbegin crbegin	rbegin crbegin	rbegin crbegin		rbegin crbegin	rbegin crbegin	rbegin crbegin	rbegin crbegin	rbegin crbegin
	rend crend	rend crend	rend crend	rend crend		rend crend	rend crend	rend crend	rend crend	rend crend
Element access	at	at	at	at					at				at
	operator[]	operator[]	operator[]	operator[]					operator[]				operator[]
	front	front	front	front	front	front										front	top
	back	back	back	back		back									top	back
Capacity	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty	empty
	size	size	size	size		size	size	size	size	size	size	size	size	size	size	size	size
	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size	max_size
	resize		resize	resize	resize	resize
	capacity		capacity								bucket_count	bucket_count	bucket_count	bucket_count
	reserve		reserve								reserve	reserve	reserve	reserve
	shrink_to_fit		shrink_to_fit	shrink_to_fit
Modifiers	clear		clear	clear	clear	clear	clear	clear	clear	clear	clear	clear	clear	clear
	insert		insert	insert	insert_after	insert	insert	insert	insert	insert	insert	insert	insert	insert
	emplace		emplace	emplace	emplace_after	emplace	emplace	emplace	emplace	emplace	emplace	emplace	emplace	emplace
	emplace_hint						emplace_hint	emplace_hint	emplace_hint	emplace_hint	emplace_hint	emplace_hint	emplace_hint	emplace_hint
	erase		erase	erase	erase_after	erase	erase	erase	erase	erase	erase	erase	erase	erase
	push_front			push_front	push_front	push_front
	emplace_front			emplace_front	emplace_front	emplace_front
	pop_front			pop_front	pop_front	pop_front										pop	pop
	push_back		push_back	push_back		push_back									push	push	push
	emplace_back		emplace_back	emplace_back		emplace_back									emplace	emplace	emplace
	pop_back		pop_back	pop_back		pop_back									pop
	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap	swap
	merge				merge	merge	merge	merge	merge	merge	merge	merge	merge	merge
	extract						extract	extract	extract	extract	extract	extract	extract	extract
List operations	splice				splice_after	splice
	remove				remove	remove
	remove_if				remove_if	remove_if
	reverse				reverse	reverse
	unique				unique	unique
	sort				sort	sort
Lookup	count						count	count	count	count	count	count	count	count
	find						find	find	find	find	find	find	find	find
	lower_bound						lower_bound	lower_bound	lower_bound	lower_bound
	upper_bound						upper_bound	upper_bound	upper_bound	upper_bound
	equal_range						equal_range	equal_range	equal_range	equal_range	equal_range	equal_range	equal_range	equal_range
Observers	key_comp						key_comp	key_comp	key_comp	key_comp
	value_comp						value_comp	value_comp	value_comp	value_comp
	hash_function										hash_function	hash_function	hash_function	hash_function
	key_eq										key_eq	key_eq	key_eq	key_eq
Allocator	get_allocator		get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator	get_allocator
Container		array	vector	deque	forward_list	list	set	multiset	map	multimap	unordered_set	unordered_multiset	unordered_map	unordered_multimap	stack	queue	priority_queue
		Sequence containers					Associative containers				Unordered associative containers				Container adaptors

(A PDF version of this table is available at File:container-library-overview-2012-12-27.pdf.)