22 Containers library [containers]

22.6 Container adaptors [container.adaptors]

22.6.6 Class template stack [stack]

22.6.6.1 Definition [stack.defn]

namespace std {
  template<class T, class Container = deque<T>>
  class stack {
  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:
    stack() : stack(Container()) {}
    explicit stack(const Container&);
    explicit stack(Container&&);
    template<class Alloc> explicit stack(const Alloc&);
    template<class Alloc> stack(const Container&, const Alloc&);
    template<class Alloc> stack(Container&&, const Alloc&);
    template<class Alloc> stack(const stack&, const Alloc&);
    template<class Alloc> stack(stack&&, const Alloc&);

    [[nodiscard]] bool empty() const    { return c.empty(); }
    size_type size()  const             { return c.size(); }
    reference         top()             { return c.back(); }
    const_reference   top() 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>
      decltype(auto) emplace(Args&&... args)
        { return c.emplace_back(std::forward<Args>(args)...); }
    void pop()                          { c.pop_back(); }
    void swap(stack& s) noexcept(is_nothrow_swappable_v<Container>)
      { using std::swap; swap(c, s.c); }
  };

  template<class Container>
    stack(Container) -> stack<typename Container::value_type, Container>;

  template<class Container, class Allocator>
    stack(Container, Allocator) -> stack<typename Container::value_type, Container>;

  template<class T, class Container, class Alloc>
    struct uses_allocator<stack<T, Container>, Alloc>
      : uses_allocator<Container, Alloc>::type { };
}