std::tuple_element<std::complex>
Defined in header <complex> | ||
|---|---|---|
template< std::size_t I, class T > struct tuple_element<I, std::complex<T>>; | (since C++26) |
The partial specializations of std::tuple_element for std::complex provide compile-time access to the underlying real and imaginary number type of a complex, using tuple-like syntax. They are provided for structured binding support. The program is ill-formed if I >= 2.
Member types
| Member type | Definition |
|---|---|
type |
T |
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_tuple_like | 202311L | (C++26) | Add tuple protocol to std::complex |
Example
#include <complex>
#include <type_traits>
static_assert([z = std::complex<float>()]
{
using T = decltype(z);
return
#if __cpp_lib_tuple_like >= 202311L
std::is_same_v<std::tuple_element_t<0, T>, float> &&
std::is_same_v<std::tuple_element_t<1, T>, float> &&
#endif
std::is_same_v<T::value_type, float>;
}());
int main() {}
See also
| Structured binding (C++17) | binds the specified names to sub-objects or tuple elements of the initializer |
|
(C++11) | obtains the element types of a tuple-like type (class template) |
|
(C++26) | obtains the size of a std::complex (class template specialization) |
|
(C++26) | obtains a reference to real or imaginary part from a std::complex (function template) |
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