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Standard library header <queue>

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C++
Standard library headers

此头文件属于 容器 库的一部分。

目录

包含文件

(C++20)
三路比较运算符 支持
(C++11)
std::initializer_list 类模板

类

适配容器以提供队列（FIFO数据结构）
（类模板）
适配容器以提供优先队列
（类模板）
(C++11)
特化 std::uses_allocator 类型特征
（类模板特化）
(C++11)
特化 std::uses_allocator 类型特征
（类模板特化）

函数

(C++20)
按字典序比较两个 queue 的值
（函数模板）
(C++11)
特化 std::swap 算法
（函数模板）
(C++11)
特化 std::swap 算法
（函数模板）

概要 

#include <compare>
#include <initializer_list>
namespace std {
  // 类模板 queue
  template<class T, class Container = deque<T>>
  class queue;
  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, three_way_comparable Container>
  compare_three_way_result_t<Container> 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>;
  // queue 的格式化器特化
  template<class CharT, class T, formattable<CharT> Container>
  struct formatter<queue<T, Container>, CharT>;
  // 类模板 priority_queue
  template<class T,
           class Container = vector<T>,
           class Compare   = less<typename Container::value_type>>
  class priority_queue;
  template<class T, class Container, class Compare>
  void swap(priority_queue<T, Container, Compare>& x,
            priority_queue<T, Container, Compare>& y) noexcept(noexcept(x.swap(y)));
  template<class T, class Container, class Compare, class Alloc>
  struct uses_allocator<priority_queue<T, Container, Compare>, Alloc>;
  // priority_queue 的格式化器特化
  template<class CharT, class T, formattable<CharT> Container, class Compare>
  struct formatter<priority_queue<T, Container, Compare>, CharT>;
}

类模板 std::queue 

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 InputIter>
    queue(InputIter first, InputIter 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 InputIter, class Alloc>
    queue(InputIter first, InputIter 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 InputIter>
  queue(InputIter, InputIter) -> queue</*iter-value-type*/<InputIter>>;
  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::<span class="me2

类模板 std::priority_queue 

namespace std {
  template<class T,
           class Container = vector<T>,
           class Compare   = less<typename Container::value_type>>
  class priority_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;
    using value_compare   = Compare;
  protected:
    Container c;
    Compare comp;
  public:
    priority_queue()
      : priority_queue(Compare())
    {
    }
    explicit priority_queue(const Compare& x)
      : priority_queue(x, Container())
    {
    }
    priority_queue(const Compare& x, const Container&);
    priority_queue(const Compare& x, Container&&);
    template<class InputIter>
    priority_queue(InputIter first, InputIter last, const Compare& x = Compare());
    template<class InputIter>
    priority_queue(InputIter first, InputIter last, const Compare& x, const Container&);
    template<class InputIter>
    priority_queue(InputIter first, InputIter last, const Compare& x, Container&&);
    template<container-compatible-range<T> R>
    priority_queue(from_range_t, R&& rg, const Compare& x = Compare());
    template<class Alloc>
    explicit priority_queue(const Alloc&);
    template<class Alloc>
    priority_queue(const Compare&, const Alloc&);
    template<class Alloc>
    priority_queue(const Compare&, const Container&, const Alloc&);
    template<class Alloc>
    priority_queue(const Compare&, Container&&, const Alloc&);
    template<class Alloc>
    priority_queue(const priority_queue&, const Alloc&);
    template<class Alloc>
    priority_queue(priority_queue&&, const Alloc&);
    template<class InputIter, class Alloc>
    priority_queue(InputIter, InputIter, const Alloc&);
    template<class InputIter, class Alloc>
    priority_queue(InputIter, InputIter, const Compare&, const Alloc&);
    template<class InputIter, class Alloc>
    priority_queue(InputIter, InputIter, const Compare&, const Container&, const Alloc&);
    template<class InputIter, class Alloc>
    priority_queue(InputIter, InputIter, const Compare&, Container&&, const Alloc&);
    template<container-compatible-range<T> R, class Alloc>
    priority_queue(from_range_t, R&& rg, const Compare&, const Alloc&);
    template<container-compatible-range<T> R, class Alloc>
    priority_queue(from_range_t, R&& rg, const Alloc&);
    bool empty() const { return c.empty(); }
    size_type size() const { return c.size(); }
    const_reference top() const { return c.front(); }
    void push(const value_type& x);
    void push(value_type&& x);
    template<container-compatible-range<T> R>
    void push_range(R&& rg);
    template<class... Args>
    void emplace(Args&&... args);
    void pop();
    void swap(priority_queue& q) noexcept(
      is_nothrow_swappable_v<Container<span class="sy1