std::tuple_size(std::array)

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

std::array

Member functions

Element access

array::at

array::operator[]

array::front

array::back

array::data

Iterators

array::beginarray::cbegin

array::endarray::cend

array::rbeginarray::crbegin

array::rendarray::crend

Capacity

array::empty

array::size

array::max_size

Modifiers

array::fill

array::swap

Non-member functions

get

swap

operator==operator!=operator<operator>operator<=operator>=

Helper classes

tuple_size

tuple_element

 

Defined in header <array>
template< class T, size_t N > class tuple_size< array<T, N> > :     public integral_constant<size_t, N> { };	(1)	(since C++11)

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

Inherited from std::integral_constant

Member constants

value [static]	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)
operator() (C++14)	returns value (public member function)

Member types

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

Example

Run this code

#include <iostream>
#include <array>
 
template<class T>
void test(T t)
{
    int a[std::tuple_size<T>::value]; // can be used at compile time
    std::cout << std::tuple_size<T>::value << '\n';
}
 
int main()
{
    std::array<float, 3> arr;
    test(arr);
}

Output:

3

See also

tuple_size	obtains the size of tuple at compile time (class template specialization)