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:
explicit stack(const Container&);
explicit stack(Container&& = 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&);
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>
reference 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>
bool operator==(const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
bool operator< (const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
bool operator!=(const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
bool operator> (const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
bool operator>=(const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
bool operator<=(const stack<T, Container>& x, const stack<T, Container>& y);
template <class T, class Container>
void swap(stack<T, Container>& x, stack<T, Container>& y) noexcept(noexcept(x.swap(y)));
template <class T, class Container, class Alloc>
struct uses_allocator<stack<T, Container>, Alloc>
: uses_allocator<Container, Alloc>::type { };
}