Namespaces
Variants
Views
Actions

Standard library header <deque>

From cppreference.com
< cpp‎ | header
 
 
Standard Library headers
Note: a slash '/' in a revision mark means that the header was deprecated and/or removed.
Language support
Concepts
<concepts> (C++20)
Diagnostics
<system_error> (C++11)

Memory management
<memory_resource> (C++17)  
Metaprogramming
<type_traits> (C++11)
<ratio> (C++11)
General utilities
<utility>
<tuple> (C++11)
<optional> (C++17)
<variant> (C++17)
<any> (C++17)
<expected> (C++23)
<bitset>

<charconv> (C++17)
<format> (C++20)
<bit> (C++20)

Strings
<cuchar> (C++11)

Containers
<array> (C++11)
<deque>
<forward_list> (C++11)
<list>
<flat_set> (C++23)
<span> (C++20)
<mdspan> (C++23)

Iterators
<iterator>
Ranges
<ranges> (C++20)
<generator> (C++23)
Algorithms
Numerics
<cfenv> (C++11)
<complex>
<numbers> (C++20)

Time
<chrono> (C++11)
Localization
<codecvt> (C++11/17)
Input/output
<filesystem> (C++17)
<cstdio>
<cinttypes> (C++11)
<strstream> (C++98/)
Regular expressions
<regex> (C++11)
Concurrency support
<stop_token> (C++20)
<thread> (C++11)
<atomic> (C++11)
<stdatomic.h> (C++23)
<mutex> (C++11)
<shared_mutex> (C++14)
<condition_variable> (C++11)  
<semaphore> (C++20)
<latch> (C++20)
<barrier> (C++20)
<future> (C++11)

C compatibility
<cstdbool> (C++11/17/20)  
<ccomplex> (C++11/17/20)
<ctgmath> (C++11/17/20)

<cstdalign> (C++11/17/20)

<ciso646> (until C++20)

 

This header is part of the containers library.

Contents

Includes

(C++20)
Three-way comparison operator support [edit]
std::initializer_list class template [edit]

Classes

double-ended queue
(class template) [edit]

Functions

(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)
lexicographically compares the values in the deque
(function template) [edit]
specializes the std::swap algorithm
(function template) [edit]
Erases all elements satisfying specific criteria
(function template) [edit]
Range access
(C++11)(C++14)
returns an iterator to the beginning of a container or array
(function template) [edit]
(C++11)(C++14)
returns an iterator to the end of a container or array
(function template) [edit]
returns a reverse iterator to the beginning of a container or array
(function template) [edit]
(C++14)
returns a reverse end iterator for a container or array
(function template) [edit]
(C++17)(C++20)
returns the size of a container or array
(function template) [edit]
(C++17)
checks whether the container is empty
(function template) [edit]
(C++17)
obtains the pointer to the underlying array
(function template) [edit]

[edit] Synopsis

#include <compare>
#include <initializer_list>
 
namespace std {
  // class template deque
  template<class T, class Allocator = allocator<T>> class deque;
 
  template<class T, class Allocator>
    bool operator==(const deque<T, Allocator>& x, const deque<T, Allocator>& y);
  template<class T, class Allocator>
    /*synth-three-way-result*/<T> operator<=>(const deque<T, Allocator>& x,
                                              const deque<T, Allocator>& y);
 
  template<class T, class Allocator>
    void swap(deque<T, Allocator>& x, deque<T, Allocator>& y)
      noexcept(noexcept(x.swap(y)));
 
  template<class T, class Allocator, class U>
    typename deque<T, Allocator>::size_type
      erase(deque<T, Allocator>& c, const U& value);
  template<class T, class Allocator, class Predicate>
    typename deque<T, Allocator>::size_type
      erase_if(deque<T, Allocator>& c, Predicate pred);
 
  namespace pmr {
    template<class T>
      using deque = std::deque<T, polymorphic_allocator<T>>;
  }
}

[edit] Class template std::deque

namespace std {
  template<class T, class Allocator = allocator<T>>
  class deque {
  public:
    // types
    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>;
 
    // construct/copy/destroy
    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 InputIt>
      deque(InputIt first, InputIt 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 InputIt>
      void assign(InputIt first, InputIt last);
    void assign(size_type n, const T& t);
    void assign(initializer_list<T>);
    allocator_type get_allocator() const noexcept;
 
    // iterators
    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;
 
    // capacity
    [[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();
 
    // element access
    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;
 
    // modifiers
    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 InputIt>
      iterator insert(const_iterator position, InputIt first, InputIt 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 InputIt, class Allocator = allocator</*iter-value-type*/<InputIt>>>
    deque(InputIt, InputIt, Allocator = Allocator())
      -> deque</*iter-value-type*/<InputIt>, Allocator>;
 
  // swap
  template<class T, class Allocator>
    void swap(deque<T, Allocator>& x, deque<T, Allocator>& y)
      noexcept(noexcept(x.swap(y)));
}