std::is_array

 

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Defined in header <type_traits>
template< class T > struct is_array;		(since C++11)

Checks whether T is an array type. Provides the member constant value which is equal to true, if T is an array type. Otherwise, value is equal to false.

Template parameters

T

-

a type to check

Helper variable template

template< class T > constexpr bool is_array_v = is_array<T>::value;		(since C++17)

Inherited from std::integral_constant

Member constants

value [static]

true if T is an array type , false otherwise (public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

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

Possible implementation

template<class T> struct is_array : std::false_type {};   template<class T> struct is_array<T[]> : std::true_type {};   template<class T, std::size_t N> struct is_array<T[N]> : std::true_type {};

Example

Run this code

#include <iostream>
#include <type_traits>
 
class A {};
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_array<A>::value << '\n';
    std::cout << std::is_array<A[3]>::value << '\n';
    std::cout << std::is_array<float>::value << '\n';
    std::cout << std::is_array<int>::value << '\n';
    std::cout << std::is_array<int[3]>::value << '\n';
}

Output:

false
true
false
false
true

See also

rank (C++11)	obtains the number of dimensions of an array type (class template)
extent (C++11)	obtains the size of an array type along a specified dimension (class template)
remove_extent (C++11)	removes one extent from the given array type (class template)
remove_all_extents (C++11)	removes all extents from the given array type (class template)
std::experimental::is_array_v (library fundamentals TS)	variable template alias of std::is_array::value (variable template)