[queue.defn]

Any sequence container supporting operations front(), back(), push_back() and pop_front() can be used to instantiate queue.

In particular, list and deque can be used.

namespace std { template<class T, class Container = deque<T>> class queue { public: using value_type = typename Container::value_type; using reference = typename Container::reference; using const_reference = typename Container::const_reference; using size_type = typename Container::size_type; using container_type = Container; protected: Container c; public: queue() : queue(Container()) {} explicit queue(const Container&); explicit queue(Container&&); template<class InputIterator> queue(InputIterator first, InputIterator last); template<container-compatible-range<T> R> queue(from_range_t, R&& rg); 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&); template<class InputIterator, class Alloc> queue(InputIterator first, InputIterator last, const Alloc&); template<container-compatible-range<T> R, class Alloc> queue(from_range_t, R&& rg, 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<container-compatible-range<T> R> void push_range(R&& rg); template<class... Args> decltype(auto) emplace(Args&&... args) { return c.emplace_back(std::forward<Args>(args)...); } void pop() { c.pop_front(); } void swap(queue& q) noexcept(is_nothrow_swappable_v<Container>) { using std::swap; swap(c, q.c); } }; template<class Container> queue(Container) -> queue<typename Container::value_type, Container>; template<class InputIterator> queue(InputIterator, InputIterator) -> queue<iter-value-type<InputIterator>>; template<ranges::input_range R> queue(from_range_t, R&&) -> queue<ranges::range_value_t<R>>; template<class Container, class Allocator> queue(Container, Allocator) -> queue<typename Container::value_type, Container>; template<class InputIterator, class Allocator> queue(InputIterator, InputIterator, Allocator) -> queue<iter-value-type<InputIterator>, deque<iter-value-type<InputIterator>, Allocator>>; template<ranges::input_range R, class Allocator> queue(from_range_t, R&&, Allocator) -> queue<ranges::range_value_t<R>, deque<ranges::range_value_t<R>, Allocator>>; template<class T, class Container, class Alloc> struct uses_allocator<queue<T, Container>, Alloc> : uses_allocator<Container, Alloc>::type { }; }

23 Containers library [containers]

23.6 Container adaptors [container.adaptors]

23.6.3 Class template queue [queue]

23.6.3.1 Definition [queue.defn]