Any sequence container supporting operations front(), back(), push_back() and pop_front() can be used to instantiate queue. In particular, list ([list]) and deque ([deque]) can be used.
namespace std { template <class T, class Container = deque<T> > class queue { public: typedef typename Container::value_type value_type; typedef typename Container::reference reference; typedef typename Container::const_reference const_reference; typedef typename Container::size_type size_type; typedef Container container_type; protected: Container c; public: explicit queue(const Container&); explicit queue(Container&& = Container()); template <class Alloc> explicit queue(const Alloc&); template <class Alloc> queue(const Container&, const Alloc&); template <class Alloc> queue(Container&&, const Alloc&); template <class Alloc> queue(const queue&, const Alloc&); template <class Alloc> queue(queue&&, const Alloc&); bool empty() const { return c.empty(); } size_type size() const { return c.size(); } reference front() { return c.front(); } const_reference front() const { return c.front(); } reference back() { return c.back(); } const_reference back() const { return c.back(); } void push(const value_type& x) { c.push_back(x); } void push(value_type&& x) { c.push_back(std::move(x)); } template <class... Args> void emplace(Args&&... args) { c.emplace_back(std::forward<Args>(args)...); } void pop() { c.pop_front(); } void swap(queue& q) noexcept(noexcept(swap(c, q.c))) { using std::swap; swap(c, q.c); } }; template <class T, class Container> bool operator==(const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> bool operator< (const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> bool operator!=(const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> bool operator> (const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> bool operator>=(const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> bool operator<=(const queue<T, Container>& x, const queue<T, Container>& y); template <class T, class Container> void swap(queue<T, Container>& x, queue<T, Container>& y) noexcept(noexcept(x.swap(y))); template <class T, class Container, class Alloc> struct uses_allocator<queue<T, Container>, Alloc> : uses_allocator<Container, Alloc>::type { }; }
explicit queue(const Container& cont);
Effects: Initializes c with cont.
explicit queue(Container&& cont = Container());
Effects: Initializes c with std::move(cont).
If uses_allocator<container_type, Alloc>::value is false the constructors in this subclause shall not participate in overload resolution.
template <class Alloc>
explicit queue(const Alloc& a);
Effects: Initializes c with a.
template <class Alloc>
queue(const container_type& cont, const Alloc& a);
Effects: Initializes c with cont as the first argument and a as the second argument.
template <class Alloc>
queue(container_type&& cont, const Alloc& a);
Effects: Initializes c with std::move(cont) as the first argument and a as the second argument.
template <class Alloc>
queue(const queue& q, const Alloc& a);
Effects: Initializes c with q.c as the first argument and a as the second argument.
template <class Alloc>
queue(queue&& q, const Alloc& a);
Effects: Initializes c with std::move(q.c) as the first argument and a as the second argument.
template <class T, class Container>
bool operator==(const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c == y.c.
template <class T, class Container>
bool operator!=(const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c != y.c.
template <class T, class Container>
bool operator< (const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c < y.c.
template <class T, class Container>
bool operator<=(const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c <= y.c.
template <class T, class Container>
bool operator> (const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c > y.c.
template <class T, class Container>
bool operator>=(const queue<T, Container>& x,
const queue<T, Container>& y);
Returns: x.c >= y.c.
template <class T, class Container>
void swap(queue<T, Container>& x, queue<T, Container>& y) noexcept(noexcept(x.swap(y)));
Effects: x.swap(y).