std::tuple_element<std::ranges::subrange>
From cppreference.com
Defined in header <ranges>
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template
<
class I, class S, ranges::subrange_kind K >
struct tuple_element< 0, ranges::subrange <I, S, K>> ; |
(1) | (since C++20) |
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template
<
class I, class S, ranges::subrange_kind K >
struct tuple_element< 0, const ranges::subrange <I, S, K>> ; |
(2) | (since C++20) |
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template
<
class I, class S, ranges::subrange_kind K >
struct tuple_element< 1, ranges::subrange <I, S, K>> ; |
(3) | (since C++20) |
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template
<
class I, class S, ranges::subrange_kind K >
struct tuple_element< 1, const ranges::subrange <I, S, K>> ; |
(4) | (since C++20) |
The partial specializations of std::tuple_element for std::ranges::subrange provide compile-time access to the iterator or sentinel type of a subrange
1,2) Obtains the iterator type, i.e.
I.3,4) Obtains the sentinel type, i.e.
S.Member types
| Member type | Definition |
type
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(1,2) I(3,4) S
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Notes
As get functions for subrange return iterators and sentinels by value, const qualifier is not added to the result types when the subrange
If the subrange is volatile-qualified, the result types are also volatile-qualified because the partial specialization for volatile or const volatile types are used. Such usage is deprecated.
Example
Run this code
#include <iterator> #include <list> #include <ranges> #include <type_traits> int main() { std::list<int> list{3, 1, 4, 1, 5, 9, 2, 6}; std::ranges::subrange subrange { std::counted_iterator{std::begin(list), 4}, std::default_sentinel }; static_assert( std::is_same_v< std::tuple_element_t<0, decltype(subrange)>, // implementation-defined type: std::counted_iterator<std::_List_iterator<int>> >); static_assert( std::is_same_v< std::tuple_element_t<1, decltype(subrange)>, std::default_sentinel_t >); }
See also
| Structured binding (C++17) | binds the specified names to sub-objects or tuple elements of the initializer |
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(C++11)
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obtains the element types of a tuple-like type (class template) |
| obtains the size of a std::ranges::subrange (class template specialization) |