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      std::is_bounded_array

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

      std::is_bounded_array is a UnaryTypeTrait.

      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.

      If the program adds specializations for std::is_bounded_array or std::is_bounded_array_v, the behavior is undefined.

      Contents

      [edit]Template parameters

      T - a type to check

      [edit]Helper variable template

      template<class T >
      constexprbool is_bounded_array_v = is_bounded_array<T>::value;
      		(since C++20)
      [edit]

      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_typebool
      typestd::integral_constant<bool, value>

      [edit]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{};

      [edit]Notes

      Feature-test macroValueStdFeature
      __cpp_lib_bounded_array_traits201902L(C++20)std::is_bounded_array, std::is_unbounded_array

      [edit]Example

      Run this code
      #include <iostream>#include <type_traits>   #define OUT(...) std::cout << #__VA_ARGS__ << " : " << __VA_ARGS__ << '\n'   class A {};   int main(){std::cout<<std::boolalpha; OUT(std::is_bounded_array_v<A>); OUT(std::is_bounded_array_v<A[]>); OUT(std::is_bounded_array_v<A[3]>); OUT(std::is_bounded_array_v<float>); OUT(std::is_bounded_array_v<int>); OUT(std::is_bounded_array_v<int[]>); OUT(std::is_bounded_array_v<int[3]>);}

      Output: 

      std::is_bounded_array_v<A> : false std::is_bounded_array_v<A[]> : false std::is_bounded_array_v<A[3]> : true std::is_bounded_array_v<float> : false std::is_bounded_array_v<int> : false std::is_bounded_array_v<int[]> : false std::is_bounded_array_v<int[3]> : true

      [edit]See also

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