3.9 KiB
[queue.defn]
23 Containers library [containers]
23.6 Container adaptors [container.adaptors]
23.6.3 Class template queue [queue]
23.6.3.1 Definition [queue.defn]
Any sequence container supporting operationsfront(),back(),push_back() andpop_front() can be used to instantiatequeue.
In particular, and can be used.
namespace std {template<class T, class Container = deque>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:constexpr queue() : queue(Container()) {}constexpr explicit queue(const Container&); constexpr explicit queue(Container&&); template constexpr queue(InputIterator first, InputIterator last); template<container-compatible-range R> constexpr queue(from_range_t, R&& rg); template constexpr explicit queue(const Alloc&); template constexpr queue(const Container&, const Alloc&); template constexpr queue(Container&&, const Alloc&); template constexpr queue(const queue&, const Alloc&); template constexpr queue(queue&&, const Alloc&); template<class InputIterator, class Alloc>constexpr queue(InputIterator first, InputIterator last, const Alloc&); template<container-compatible-range R, class Alloc>constexpr queue(from_range_t, R&& rg, const Alloc&); constexpr bool empty() const { return c.empty(); }constexpr size_type size() const { return c.size(); }constexpr reference front() { return c.front(); }constexpr const_reference front() const { return c.front(); }constexpr reference back() { return c.back(); }constexpr const_reference back() const { return c.back(); }constexpr void push(const value_type& x) { c.push_back(x); }constexpr void push(value_type&& x) { c.push_back(std::move(x)); }template<container-compatible-range R> constexpr void push_range(R&& rg); template<class... Args>constexpr decltype(auto) emplace(Args&&... args){ return c.emplace_back(std::forward(args)...); }constexpr void pop() { c.pop_front(); }constexpr void swap(queue& q) noexcept(is_nothrow_swappable_v){ using std::swap; swap(c, q.c); }}; template queue(Container) -> queue<typename Container::value_type, Container>; template queue(InputIterator, InputIterator) -> queue<iter-value-type>; template<ranges::input_range R> queue(from_range_t, R&&) -> queue<ranges::range_value_t>; 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, deque<iter-value-type, Allocator>>; template<ranges::input_range R, class Allocator> queue(from_range_t, R&&, Allocator)-> queue<ranges::range_value_t, deque<ranges::range_value_t, Allocator>>; template<class T, class Container, class Alloc>struct uses_allocator<queue<T, Container>, Alloc>: uses_allocator<Container, Alloc>::type { };}