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std::deque

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< cpp‎ | container
Revision as of 22:50, 31 May 2013 by P12bot (Talk | contribs)

Defined in header <deque>
template<

    class T,
    class Allocator = std::allocator<T>

> class deque;

std::deque (double-ended queue) is an indexed sequence container that allows fast insertion and deletion at both its beginning and its end. In addition, insertion and deletion at either end of a deque never invalidates pointers or references to the rest of the elements.

As opposed to std::vector, the elements of a deque are not stored contiguously: typical implementations use a sequence of individually allocated fixed-size arrays.

The storage of a deque is automatically expanded and contracted as needed. Expansion of a deque is cheaper than the expansion of a std::vector because it does not involve copying of the existing elements to a new memory location.

The complexity (efficiency) of common operations on deques is as follows:

  • Random access - constant O(1)
  • Insertion or removal of elements at the end or beginning - amortized constant O(1)
  • Insertion or removal of elements - linear O(n)

std::deque meets the requirements of Container, AllocatorAwareContainer, SequenceContainer and ReversibleContainer.

Contents

Template parameters

T - The type of the elements.
T must meet the requirements of CopyAssignable and CopyConstructible. (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 meets the requirements of MoveConstructible and MoveAssignable, but many member functions impose stricter requirements. (since C++11)

[edit]

Allocator - An allocator that is used to acquire memory to store the elements. The type must meet the requirements of Allocator. [edit]

Member types

Member type Definition
value_type T [edit]
allocator_type Allocator [edit]
size_type Unsigned integral type (usually std::size_t) [edit]
difference_type Signed integer type (usually std::ptrdiff_t) [edit]
reference Allocator::reference (until C++11)
value_type& (since C++11) [edit]
const_reference Allocator::const_reference (until C++11)
const value_type& (since C++11) [edit]
pointer Allocator::pointer (until C++11)
std::allocator_traits<Allocator>::pointer (since C++11) [edit]
const_pointer Allocator::const_pointer (until C++11)
std::allocator_traits<Allocator>::const_pointer (since C++11) [edit]
iterator RandomAccessIterator [edit]
const_iterator Constant random access iterator [edit]
reverse_iterator std::reverse_iterator<iterator> [edit]
const_reverse_iterator std::reverse_iterator<const_iterator> [edit]

Member functions

constructs the deque
(public member function) [edit]
destructs the deque
(public member function) [edit]
assigns values to the container
(public member function) [edit]
assigns values to the container
(public member function) [edit]
returns the associated allocator
(public member function) [edit]
Element access
access specified element with bounds checking
(public member function) [edit]
access specified element
(public member function) [edit]
access the first element
(public member function) [edit]
access the last element
(public member function) [edit]
Iterators
returns an iterator to the beginning
(public member function) [edit]
returns an iterator to the end
(public member function) [edit]
returns a reverse iterator to the beginning
(public member function) [edit]
returns a reverse iterator to the end
(public member function) [edit]
Capacity
checks whether the container is empty
(public member function) [edit]
returns the number of elements
(public member function) [edit]
returns the maximum possible number of elements
(public member function) [edit]
reduces memory usage by freeing unused memory
(public member function) [edit]
Modifiers
clears the contents
(public member function) [edit]
inserts elements
(public member function) [edit]
(C++11)
constructs element in-place
(public member function) [edit]
erases elements
(public member function) [edit]
adds elements to the end
(public member function) [edit]
constructs elements in-place at the end
(public member function) [edit]
removes the last element
(public member function) [edit]
inserts elements to the beginning
(public member function) [edit]
constructs elements in-place at the beginning
(public member function) [edit]
removes the first element
(public member function) [edit]
changes the number of elements stored
(public member function) [edit]
swaps the contents
(public member function) [edit]

Non-member functions

lexicographically compares the values in the deque
(function template) [edit]
specializes the std::swap algorithm
(function template) [edit]