std:: tuple_element <std::complex>

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C++
Numerics library
Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Data-parallel types ( simd ) (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array ( valarray )
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(C++17)
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Interpolations
(C++20)
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Saturation arithmetic
(C++26)
(C++26)
(C++26)
(C++26)
(C++26)

Generic numeric operations
Bit operations
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
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

Run this code 
#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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