std::get(std::array) - cppreference.com (original) (raw)
| Defined in header | ||
|---|---|---|
| template< std::size_t I, class T, std::size_t N >T& get( std::array<T,N>& a ) noexcept; | (1) | (since C++11) (constexpr since C++14) |
| template< std::size_t I, class T, std::size_t N >T&& get( std::array<T,N>&& a ) noexcept; | (2) | (since C++11) (constexpr since C++14) |
| template< std::size_t I, class T, std::size_t N > const T& get( const std::array<T,N>& a ) noexcept; | (3) | (since C++11) (constexpr since C++14) |
| template< std::size_t I, class T, std::size_t N > const T&& get( const std::array<T,N>&& a ) noexcept; | (4) | (since C++11) (constexpr since C++14) |
Extracts the Ith element from the array using tuple-like interface.
I must be an integer value in range [0, N). This is enforced at compile time as opposed to at() or operator[].
[edit] Parameters
| a | - | array whose contents to extract |
|---|
[edit] Return value
A reference to the Ith element of a.
[edit] Complexity
Constant.
[edit] Example
#include #include constexpr std::array v{1, 2, 3}; static_assert(get<0>(v) == 1 && get<1>(v) == 2 && get<2>(v) == 3); int main() { std::array<int, 3> a; // set values: get<0>(a) = 1, get<1>(a) = 2, get<2>(a) = 3; // get values: std::cout << '(' << get<0>(a) << ',' << get<1>(a) << ',' << get<2>(a) << ")\n"; }
Output:
[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 2485 | C++11 | there are no overloads for const array&& | the overloads are added |
[edit] See also
| Structured binding (C++17) | binds the specified names to sub-objects or tuple elements of the initializer[edit] |
|---|---|
| operator[] | access specified element (public member function) [edit] |
| at | access specified element with bounds checking (public member function) [edit] |
| get(std::tuple)(C++11) | tuple accesses specified element (function template) [edit] |
| get(std::pair)(C++11) | accesses an element of a pair (function template) [edit] |
| get(std::variant)(C++17) | reads the value of the variant given the index or the type (if the type is unique), throws on error (function template) [edit] |
| get(std::ranges::subrange)(C++20) | obtains iterator or sentinel from a std::ranges::subrange (function template) [edit] |
| get(std::complex)(C++26) | obtains a reference to real or imaginary part from a std::complex (function template) [edit] |