class template
<queue>

std::queue

template <class T, class Container = deque<T> > class queue;
FIFO queue
queues are a type of container adaptor, specifically designed to operate in a FIFO context (first-in first-out), where elements are inserted into one end of the container and extracted from the other.

queues are implemented as containers adaptors, which are classes that use an encapsulated object of a specific container class as its underlying container, providing a specific set of member functions to access its elements. Elements are pushed into the "back" of the specific container and popped from its "front".

The underlying container may be one of the standard container class template or some other specifically designed container class. The container shall support the following operations:
  • front
  • back
  • push_back
  • pop_front

The standard container classes deque and list fulfill these requirements. By default, if no container class is specified for a particular queue class instantiation, the standard container deque is used.

Template parameters

T
Type of the elements.
Aliased as member type queue::value_type.
Container
Type of the internal underlying container object where the elements are stored.
Its value_type shall be T.
Aliased as member type queue::container_type.

Member types

member typedefinitionnotes
value_typeThe first template parameter (T)Type of the elements
container_typeThe second template parameter (Container)Type of the underlying container
size_typean unsigned integral typeusually the same as size_t
member typedefinitionnotes
value_typeThe first template parameter (T)Type of the elements
container_typeThe second template parameter (Container)Type of the underlying container
referencecontainer_type::referenceusually, value_type&
const_referencecontainer_type::const_referenceusually, const value_type&
size_typean unsigned integral typeusually, the same as size_t

Member functions

(constructor)
Construct queue (public member function )
empty
Test whether container is empty (public member function )
size
Return size (public member function )
front
Access next element (public member function )
back
Access last element (public member function )
push
Insert element (public member function )
emplace
Construct and insert element (public member function )
pop
Remove next element (public member function )
swap
Swap contents (public member function )

Non-member function overloads

relational operators
Relational operators for queue (function )
swap (queue)
Exchange contents of queues (public member function )

Non-member class specializations

uses_allocator<queue>
Uses allocator for queue (class template )

C++