[#VecDeque]
= VecDeque
:mrdocs:

Data structure largely mimicking std::deque, but using single preallocated ring buffer.

== Synopsis

Declared in `<util/vecdeque.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<typename T>
class VecDeque;
----

== Description

* More efficient and better memory locality than std::deque.
* Most operations ({push_,pop_,emplace_,}{front,back}(), operator[], ...) are O(1), unless reallocation is needed (in which case they are O(n)).
* Supports reserve(), capacity(), shrink_to_fit() like vectors.
* No iterator support.
* Data is not stored in a single contiguous block, so no data().

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:VecDeque/2constructor-08.adoc[`VecDeque`]         [.small]#[constructor]#
| Constructors
| xref:VecDeque/2destructor.adoc[`~VecDeque`] [.small]#[destructor]#
| Destroy a deque.
| xref:VecDeque/operator_assign-0d.adoc[`operator=`] 
| Assignment operators
| xref:VecDeque/back-09.adoc[`back`] 
| `back` overloads
| xref:VecDeque/capacity.adoc[`capacity`] 
| Get the capacity of this deque (maximum size it can have without reallocating).
| xref:VecDeque/clear.adoc[`clear`] 
| Resize the deque to be size 0. The capacity will remain unchanged.
| xref:VecDeque/emplace_back.adoc[`emplace_back`] 
| Construct a new element at the end of the deque.
| xref:VecDeque/emplace_front.adoc[`emplace_front`] 
| Construct a new element at the beginning of the deque.
| xref:VecDeque/empty.adoc[`empty`] 
| Test whether the contents of this deque is empty.
| xref:VecDeque/front-01.adoc[`front`] 
| `front` overloads
| xref:VecDeque/operator_subs-09.adoc[`operator[]`] 
| Subscript operators
| xref:VecDeque/pop_back.adoc[`pop_back`] 
| Remove the last element of the deque. Requires !empty().
| xref:VecDeque/pop_front.adoc[`pop_front`] 
| Remove the first element of the deque. Requires !empty().
| xref:VecDeque/push_back-01.adoc[`push_back`] 
| `push_back` overloads
| xref:VecDeque/push_front-04.adoc[`push_front`] 
| `push_front` overloads
| xref:VecDeque/reserve.adoc[`reserve`] 
| Increase the capacity to capacity. Capacity will not shrink.
| xref:VecDeque/resize.adoc[`resize`] 
| Resize the deque to be exactly size size (adding default‐constructed elements if needed).
| xref:VecDeque/shrink_to_fit.adoc[`shrink_to_fit`] 
| Make the capacity equal to the size. The contents does not change.
| xref:VecDeque/size.adoc[`size`] 
| Get the number of elements in this deque.
| xref:VecDeque/swap.adoc[`swap`] 
| Swap two deques.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `xref:operator_3way-056.adoc[operator<=>]`
| Comparison between two deques, implementing lexicographic ordering on the contents.
| `xref:operator_eq-0a6.adoc[operator==]`
| Equality comparison between two deques (only compares size+contents, not capacity).
| `xref:swap-01.adoc[swap]`
| Non‐member version of swap.
|===


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