std::is_bounded_array
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   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.
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
Run this code
#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)  |