home | help 
std::is_array(3)	       C++ Standard Libary		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_ar-
     ray_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)

http://cppreference.com 	   2024.06.10			std::is_array(3)
home | help