std::is_array(3)

NAME
std::is_array - std::is_array

Synopsis
   Defined in header <type_traits>
   template< class T > (since C++11)
   struct is_array;
   std::is_array is a UnaryTypeTrait.
   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.
   If the program adds specializations for std::is_array or std::is_array_v, the
   behavior is undefined.

Template parameters
   T - a type to check
   Helper variable template
   template< class T > (since C++17)
   inline constexpr bool is_array_v = is_array<T>::value; Inherited from std::integral_constant

Member constants
   value true if T is an array type, false otherwise
   [static] (public static member constant)

Member functions
   operator bool converts the object to bool, returns value
                 (public member function)
   operator() returns value
   (C++14) (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 <array>
 #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[]>::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[]>::value << '\n';
     std::cout << std::is_array<int[3]>::value << '\n';
     std::cout << std::is_array<std::array<int, 3>>::value << '\n';
 }

Output:
 false
 true
 true
 false
 false
 true
 true
 false

See also
   is_bounded_array checks if a type is an array type of known bound
   (C++20) (class template)
   is_unbounded_array checks if a type is an array type of unknown bound
   (C++20) (class template)
   rank obtains the number of dimensions of an array type
   (C++11) (class template)
   extent obtains the size of an array type along a specified dimension
   (C++11) (class template)
   remove_extent removes one extent from the given array type
   (C++11) (class template)
   remove_all_extents removes all extents from the given array type
   (C++11) (class template)