Difference between revisions of "cpp/container/array/tuple element"
From cppreference.com
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| − | + | struct tuple_element<I, std::array<T,N>> | |
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Latest revision as of 13:47, 6 December 2023
| Defined in header <array>
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| template< std::size_t I, class T, std::size_t N > struct tuple_element< I, std::array<T, N> >; |
(since C++11) | |
Provides compile-time indexed access to the type of the elements of the array using tuple-like interface.
Contents |
[edit] Member types
| Member type | Definition |
| type | the type of elements of the array |
[edit] Possible implementation
template<std::size_t I, class T> struct tuple_element; template<std::size_t I, class T, std::size_t N> struct tuple_element<I, std::array<T,N>> { using type = T; }; |
[edit] Example
Run this code
#include <array> #include <tuple> #include <type_traits> int main() { // define array and get the type of the element at position 0 std::array<int, 10> data{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; using T = std::tuple_element<0, decltype(data)>::type; // int static_assert(std::is_same_v<T, int>); const auto const_data = data; using CT = std::tuple_element<0, decltype(const_data)>::type; // const int // the result of tuple_element depends on the cv-qualification of the tuple-like type static_assert(!std::is_same_v<T, CT>); static_assert(std::is_same_v<CT, const int>); }
[edit] See also
| Structured binding (C++17) | binds the specified names to sub-objects or tuple elements of the initializer |
| obtains the type of the specified element (class template specialization) | |
obtains the type of the elements of pair (class template specialization) |
