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deduction guides for std::stack

From cppreference.com
< cpp‎ | container‎ | stack
 
 
 
 
Defined in header <stack>
template<class Container >

stack( Container )

    -> stack<typename Container::value_type, Container>;
(1) (since C++17)
template<class Container, class Alloc >

stack( Container, Alloc )

    -> stack<typename Container::value_type, Container>;
(2) (since C++17)
template<class InputIt >

stack( InputIt, InputIt )

    -> stack<typenamestd::iterator_traits<InputIt>::value_type>;
(3) (since C++23)
template<class InputIt, class Alloc >

stack( InputIt, InputIt, Alloc )
    -> stack<typenamestd::iterator_traits<InputIt>::value_type,

       std::deque<typenamestd::iterator_traits<InputIt>::value_type, Alloc>>;
(4) (since C++23)
template<ranges::input_range R >

stack(std::from_range_t, R&&)

    -> stack<ranges::range_value_t<R>>;
(5) (since C++23)
template<ranges::input_range R, class Allocator >

stack(std::from_range_t, R&&, Allocator )
    -> stack<ranges::range_value_t<R>,

       std::deque<ranges::range_value_t<R>, Allocator>>;
(6) (since C++23)

These deduction guides are provided for stack to allow deduction from underlying container type.

1) Deduces underlying container type from the argument.
2) Same as (1), except that the allocator is provided.
3) Deduces the element type from the iterator, using std::deque<typenamestd::iterator_traits<InputIt>::value_type> as the underlying container type.
4) Same as (3), except that the allocator is provided.
5) Deduces the element type from a std::from_range_t tag and an input_range.
6) Same as (5), except that the allocator is provided.

These overloads participate in overload resolution only if

Note: the extent to which the library determines that a type does not satisfy LegacyInputIterator is unspecified, except that as a minimum integral types do not qualify as input iterators. Likewise, the extent to which it determines that a type does not satisfy Allocator is unspecified, except that as a minimum the member type Alloc::value_type must exist and the expression std::declval<Alloc&>().allocate(std::size_t{}) must be well-formed when treated as an unevaluated operand.

[edit]Notes

Feature-test macro ValueStdFeature
__cpp_lib_adaptor_iterator_pair_constructor202106L(C++23)Iterator pair constructors for std::queue and std::stack; overloads (2) and (4)
__cpp_lib_containers_ranges202202L(C++23)Ranges-aware construction and insertion; overloads (5) and (6)

[edit]Example

#include <stack>#include <vector>   int main(){std::vector<int> v ={1, 2, 3, 4};std::stack s{v};// guide #1 deduces std::stack<int, vector<int>>}
close