# std::queue< _Tp, _Sequence > Class Template Reference
[Containers, Sequences]

A standard container giving FIFO behavior. More...

`#include <stl_queue.h>`

List of all members.

## Public Methods

| queue (const _Sequence &__c=_Sequence())
| Default constructor creates no elements.
bool | empty () const
size_type | size () const
reference | front ()
const_reference | front () const
reference | back ()
const_reference | back () const
void | push (const value_type &__x)
| Add data to the end of the %queue.
void | pop ()
| Removes first element.

## Protected Attributes

_Sequence | c

## Detailed Description

### template<typename _Tp, typename _Sequence>
class std::queue< _Tp, _Sequence >

A standard container giving FIFO behavior.

Meets many of the requirements of a container, but does not define anything to do with iterators. Very few of the other standard container interfaces are defined.

This is not a true container, but an adaptor. It holds another container, and provides a wrapper interface to that container. The wrapper is what enforces strict first-in-first-out %queue behavior.

The second template parameter defines the type of the underlying sequence/container. It defaults to std::deque, but it can be any type that supports `front,` `back,` `push_back,` and `pop_front,` such as std::list or an appropriate user-defined type.

Members not found in "normal" containers are `container_type,` which is a typedef for the second Sequence parameter, and `push` and `pop,` which are standard %queue/FIFO operations.

Definition at line 105 of file stl_queue.h.

## Constructor & Destructor Documentation

template<typename _Tp, typename _Sequence>
std::queue< _Tp, _Sequence >::queue | ( | const _Sequence & | __c = _Sequence() | ) | `[inline, explicit]`

| Default constructor creates no elements. Definition at line 143 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

## Member Function Documentation

template<typename _Tp, typename _Sequence>
const_reference std::queue< _Tp, _Sequence >::back | ( |  | ) | const`[inline]`

| Returns a read-only (constant) reference to the data at the last element of the %queue. Definition at line 182 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
reference std::queue< _Tp, _Sequence >::back | ( |  | ) | `[inline]`

| Returns a read/write reference to the data at the last element of the %queue. Definition at line 175 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
bool std::queue< _Tp, _Sequence >::empty | ( |  | ) | const`[inline]`

| Returns true if the %queue is empty. Definition at line 150 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
const_reference std::queue< _Tp, _Sequence >::front | ( |  | ) | const`[inline]`

| Returns a read-only (constant) reference to the data at the first element of the %queue. Definition at line 168 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
reference std::queue< _Tp, _Sequence >::front | ( |  | ) | `[inline]`

| Returns a read/write reference to the data at the first element of the %queue. Definition at line 161 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
void std::queue< _Tp, _Sequence >::pop | ( |  | ) | `[inline]`

| Removes first element. This is a typical %queue operation. It shrinks the %queue by one. The time complexity of the operation depends on the underlying sequence. Note that no data is returned, and if the first element's data is needed, it should be retrieved before pop() is called. Definition at line 207 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
void std::queue< _Tp, _Sequence >::push | ( | const value_type & | __x | ) | `[inline]`

Add data to the end of the %queue.

Parameters:

  x | Data to be added.

This is a typical %queue operation. The function creates an element at the end of the %queue and assigns the given data to it. The time complexity of the operation depends on the underlying sequence.

Definition at line 194 of file stl_queue.h.

References std::queue< _Tp, _Sequence >::c .

template<typename _Tp, typename _Sequence>
size_type std::queue< _Tp, _Sequence >::size | ( |  | ) | const`[inline]`

| Returns the number of elements in the %queue. Definition at line 154 of file stl_queue.h. References std::queue< _Tp, _Sequence >::c .

## Member Data Documentation

template<typename _Tp, typename _Sequence>
_Sequence std::queue< _Tp, _Sequence >::c`[protected]`

'c' is the underlying container. Maintainers wondering why this isn't uglified as per style guidelines should note that this name is specified in the standard, [23.2.3.1]. (Why? Presumably for the same reason that it's protected instead of private: to allow derivation. But none of the other containers allow for derivation. Odd.)

Definition at line 136 of file stl_queue.h.

Referenced by std::queue< _Tp, _Sequence >::back() , std::queue< _Tp, _Sequence >::empty() , std::queue< _Tp, _Sequence >::front() , std::operator==() , std::queue< _Tp, _Sequence >::pop() , std::queue< _Tp, _Sequence >::push() , std::queue< _Tp, _Sequence >::queue() , and std::queue< _Tp, _Sequence >::size() .

The documentation for this class was generated from the following file:

- stl_queue.h