Defined in header <array>
template< class T, std::size_t N >
struct tuple_size< std::array<T, N> > :
    std::integral_constant<std::size_t, N>
{ };
(since C++11)

Provides access to the number of elements in an std::array as a compile-time constant expression.

Helper variable template

template< class T >
inline constexpr std::size_t tuple_size_v = tuple_size<T>::value;
(since C++17)

Inherited from std::integral_constant

Member constants

N, the number of elements in the array
(public static member constant)

Member functions

operator std::size_t
converts the object to std::size_t, returns value
(public member function)
returns value
(public member function)

Member types

Type Definition
value_type std::size_t
type std::integral_constant<std::size_t, value>


#include <array>
int main()
    auto arr = std::to_array("ABBA");
    static_assert(std::tuple_size<decltype(arr)>{} == 5);

See also

Structured binding (C++17) binds the specified names to sub-objects or tuple elements of the initializer
obtains the size of tuple at compile time
(class template specialization)

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