std::stack - cppreference.com (original) (raw)

| | | | | ------------------------------------------------------------------------------------------------------------------------------------------------ | | | | template< class T, class Container = std::deque<T> > class stack; | | |

The std::stack class is a container adaptor that gives the programmer the functionality of a stack - specifically, a LIFO (last-in, first-out) data structure.

The class template acts as a wrapper to the underlying container - only a specific set of functions is provided. The stack pushes and pops the element from the back of the underlying container, known as the top of the stack.

All member functions of std::stack are constexpr: it is possible to create and use std::stack objects in the evaluation of a constant expression.However, std::stack objects generally cannot be constexpr, because any dynamically allocated storage must be released in the same evaluation of constant expression. (since C++26)

Contents

[edit] Template parameters

T - The type of the stored elements. The program is ill-formed if T is not the same type as Container::value_type.
Container - The type of the underlying container to use to store the elements. The container must satisfy the requirements of SequenceContainer. Additionally, it must provide the following functions with the usual semantics: back(), e.g., std::vector::back(), push_back(), e.g., std::deque::push_back(), pop_back(), e.g., std::list::pop_back(). The standard containers std::vector (including std::vector), std::deque and std::list satisfy these requirements. By default, if no container class is specified for a particular stack class instantiation, the standard container std::deque is used.

[edit] Member types

Type Definition
container_type Container[edit]
value_type Container::value_type[edit]
size_type Container::size_type[edit]
reference Container::reference[edit]
const_reference Container::const_reference[edit]

[edit] Member objects

Member Description
the underlying container (protected member object) [edit]

[edit] Member functions

(constructor) constructs the stack (public member function) [edit]
(destructor) destructs the stack (public member function) [edit]
operator= assigns values to the container adaptor (public member function) [edit]
Element access
top accesses the top element (public member function) [edit]
Capacity
empty checks whether the container adaptor is empty (public member function) [edit]
size returns the number of elements (public member function) [edit]
Modifiers
push inserts element at the top (public member function) [edit]
push_range(C++23) inserts a range of elements at the top (public member function) [edit]
emplace(C++11) constructs element in-place at the top (public member function) [edit]
pop removes the top element (public member function) [edit]
swap(C++11) swaps the contents (public member function) [edit]

[edit] Non-member functions

[edit] Helper classes

[edit] Notes

Feature-test macro Value Std Feature
__cpp_lib_containers_ranges 202202L (C++23) Ranges construction and insertion for containers
__cpp_lib_constexpr_stack 202502L (C++26) constexpr std::stack

[edit] Example

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 307 C++98 Container could not be std::vector allowed
LWG 2566 C++98 Missing the requirement for Container::value_type ill-formed if T is not the same type as Container::value_type

[edit] See also