Standard library header <stack>

 

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Standard library headers

Language support <cfloat> <climits> <compare> (C++20) <contracts> (C++26) <coroutine> (C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint> (C++11) <cstdlib> <exception> <initializer_list> (C++11)   <limits> <new> <source_location> (C++20) <stdfloat> (C++23) <typeinfo> <version> (C++20) Concepts <concepts> (C++20) Diagnostics <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) Memory management <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) Metaprogramming <meta> (C++26) <ratio> (C++11) <type_traits> (C++11)

General utilities <any> (C++17) <bitset> <bit> (C++20) <charconv> (C++17) <expected> (C++23) <format> (C++20) <functional> <optional> (C++17) <stdbit.h> (C++26) <tuple> (C++11) <typeindex> (C++11) <utility> <variant> (C++17) Containers <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <hive> (C++26) <inplace_vector> (C++26)   <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> Iterators <iterator> Ranges <generator> (C++23) <ranges> (C++20)

Algorithms <algorithm> <numeric> Strings <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> Text processing <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)   Numerics <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <simd> (C++26) <stdckdint.h> (C++26) <valarray> Time <chrono> (C++11) <ctime> C compatibility <ccomplex> (C++11/17/20*) <ciso646> (until C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

Input/output <cinttypes> (C++11) <cstdio> <filesystem> (C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print> (C++23) <spanstream> (C++23) <sstream> <streambuf> <strstream> (C++98/26*) <syncstream> (C++20) Concurrency support <atomic> (C++11) <barrier> (C++20) <condition_variable> (C++11) <future> (C++11) <hazard_pointer> (C++26) <latch> (C++20) <mutex> (C++11) <rcu> (C++26) <semaphore> (C++20) <shared_mutex> (C++14) <stdatomic.h> (C++23) <stop_token> (C++20) <thread> (C++11) Execution support <execution> (C++17)

 

See More

This header is part of the containers library.

Includes
<compare> (C++20)	Three-way comparison operator support
<initializer_list> (C++11)	std::initializer_list class template
Classes
stack	adapts a container to provide stack (LIFO data structure) (class template)
std::uses_allocator<std::stack> (C++11)	specializes the std::uses_allocator type trait (class template specialization)
Functions
operator==operator!=operator<operator<=operator>operator>=operator<=> (C++20)	lexicographically compares the values of two stacks (function template)
std::swap(std::stack) (C++11)	specializes the std::swap algorithm (function template)

Synopsis

#include <compare>
#include <initializer_list>

namespace std {
  // class template stack
  template<class T, class Container = deque<T>> class stack;

  template<class T, class Container>
  constexpr bool operator==(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, class Container>
  constexpr bool operator!=(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, class Container>
  constexpr bool operator<(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, class Container>
  constexpr bool operator>(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, class Container>
  constexpr bool operator<=(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, class Container>
  constexpr bool operator>=(const stack<T, Container>& x, const stack<T, Container>& y);
  template<class T, three_way_comparable Container>
  constexpr compare_three_way_result_t<Container> operator<=>(
    const stack<T, Container>& x, const stack<T, Container>& y);

  template<class T, class Container>
  constexpr 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>;

  // formatter specialization for stack
  template<class CharT, class T, formattable<CharT> Container>
  struct formatter<stack<T, Container>, CharT>;

  template<class T, class Container>
  constexpr bool enable_nonlocking_formatter_optimization<stack<T, Container>> = false;
}

Class template std::stack

namespace std {
  template<class T, class Container = deque<T>> class stack
  {
  public:
    using value_type = Container::value_type;
    using reference = Container::reference;
    using const_reference = Container::const_reference;
    using size_type = Container::size_type;
    using container_type = Container;

  protected:
    Container c;

  public:
    constexpr stack()
      : stack(Container())
    {
    }
    constexpr explicit stack(const Container&);
    constexpr explicit stack(Container&&);
    template<class InputIter> constexpr stack(InputIter first, InputIter last);
    template<container-compatible-range<T> R> constexpr stack(from_range_t, R&& rg);
    template<class Alloc> constexpr explicit stack(const Alloc&);
    template<class Alloc> constexpr stack(const Container&, const Alloc&);
    template<class Alloc> constexpr stack(Container&&, const Alloc&);
    template<class Alloc> constexpr stack(const stack&, const Alloc&);
    template<class Alloc> constexpr stack(stack&&, const Alloc&);
    template<class InputIter, class Alloc>
    constexpr stack(InputIter first, InputIter last, const Alloc&);
    template<container-compatible-range<T> R, class Alloc>
    constexpr stack(from_range_t, R&& rg, const Alloc&);

    constexpr bool empty() const { return c.empty(); }
    constexpr size_type size() const { return c.size(); }
    constexpr reference top() { return c.back(); }
    constexpr const_reference top() 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<T> R> constexpr void push_range(R&& rg);
    template<class... Args> constexpr decltype(auto) emplace(Args&&... args)
    {
      return c.emplace_back(std::forward<Args>(args)...);
    }
    constexpr void pop() { c.pop_back(); }
    constexpr 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 InputIter>
  stack(InputIter, InputIter) -> stack</*iter-value-type*/<InputIter>>;

  template<ranges::input_range R>
  stack(from_range_t, R&&) -> stack<ranges::range_value_t<R>>;

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

  template<class InputIter, class Allocator>
  stack(InputIter, InputIter, Allocator)
    -> stack</*iter-value-type*/<InputIter>,
             deque</*iter-value-type*/<InputIter>, Allocator>>;

  template<ranges::input_range R, class Allocator>
  stack(from_range_t, R&&, Allocator)
    -> stack<ranges::range_value_t<R>, deque<ranges::range_value_t<R>, Allocator>>;

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