In addition, it supports constant time insert and erase operations at the beginning or the end;
insert and erase in the middle take linear time
. That is, a deque is especially optimized for pushing and popping elements at the beginning and end
. Storage management is handled automatically
. A
deque
meets all of the requirements of a container, of a reversible container
(given in tables in
[container.requirements]), of a sequence container,
including the optional sequence container requirements (
[sequence.reqmts]), and of an allocator-aware container (Table
76)
. Descriptions are provided here only for operations on
deque
that are not described in one of these tables
or for operations where there is additional semantic information
.
namespace std {
template<class T, class Allocator = allocator<T>>
class deque {
public:
using 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;
using difference_type = implementation-defined;
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>;
deque() : deque(Allocator()) { }
explicit deque(const Allocator&);
explicit deque(size_type n, const Allocator& = Allocator());
deque(size_type n, const T& value, const Allocator& = Allocator());
template<class InputIterator>
deque(InputIterator first, InputIterator last, const Allocator& = Allocator());
deque(const deque& x);
deque(deque&&);
deque(const deque&, const Allocator&);
deque(deque&&, const Allocator&);
deque(initializer_list<T>, const Allocator& = Allocator());
~deque();
deque& operator=(const deque& x);
deque& operator=(deque&& x)
noexcept(allocator_traits<Allocator>::is_always_equal::value);
deque& operator=(initializer_list<T>);
template<class InputIterator>
void assign(InputIterator first, InputIterator last);
void assign(size_type n, const T& t);
void assign(initializer_list<T>);
allocator_type get_allocator() const noexcept;
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;
[[nodiscard]] bool empty() const noexcept;
size_type size() const noexcept;
size_type max_size() const noexcept;
void resize(size_type sz);
void resize(size_type sz, const T& c);
void shrink_to_fit();
reference operator[](size_type n);
const_reference operator[](size_type n) const;
reference at(size_type n);
const_reference at(size_type n) const;
reference front();
const_reference front() const;
reference back();
const_reference back() const;
template<class... Args> reference emplace_front(Args&&... args);
template<class... Args> reference emplace_back(Args&&... args);
template<class... Args> iterator emplace(const_iterator position, Args&&... args);
void push_front(const T& x);
void push_front(T&& x);
void push_back(const T& x);
void push_back(T&& x);
iterator insert(const_iterator position, const T& x);
iterator insert(const_iterator position, T&& x);
iterator insert(const_iterator position, size_type n, const T& x);
template<class InputIterator>
iterator insert(const_iterator position, InputIterator first, InputIterator last);
iterator insert(const_iterator position, initializer_list<T>);
void pop_front();
void pop_back();
iterator erase(const_iterator position);
iterator erase(const_iterator first, const_iterator last);
void swap(deque&)
noexcept(allocator_traits<Allocator>::is_always_equal::value);
void clear() noexcept;
};
template<class InputIterator, class Allocator = allocator<iter-value-type<InputIterator>>>
deque(InputIterator, InputIterator, Allocator = Allocator())
-> deque<iter-value-type<InputIterator>, Allocator>;
template<class T, class Allocator>
void swap(deque<T, Allocator>& x, deque<T, Allocator>& y)
noexcept(noexcept(x.swap(y)));
}