std::is_bounded_array

< cpp‎ | types
Defined in header <type_traits>
template< class T >
struct is_bounded_array;
 (since C++20)

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

The behavior of a program that adds specializations for is_bounded_array or is_bounded_array_v is undefined.

Template parameters

T - a type to check

Helper variable template

template< class T >
inline constexpr bool is_bounded_array_v = is_bounded_array<T>::value;
 (since C++20)

Inherited from std::integral_constant

Member constants

value
[static]
 true if T is an array type of known bound , 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_bounded_array: std::false_type {};
 
template<class T, std::size_t N>
struct is_bounded_array<T[N]> : std::true_type {};

Example

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

Output:

false
false
true
false
false
false
true

See also

(C++11)
 checks if a type is an array type
(class template)
(C++20)
 checks if a type is an array type of unknown bound
(class template)
(C++11)
 obtains the size of an array type along a specified dimension
(class template)