std::tuple_size(std::array)

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C++ Standard Library
Containers library
std::array
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.

Contents

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)

Member types

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

[edit] Example 

#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

[edit] See also

obtains the size of tuple at compile time
(class template specialization)
Retrieved from "http://en.cppreference.com/w/cpp/container/array/tuple_size"