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std::remove_extent(3)	       C++ Standard Libary	   std::remove_extent(3)

NAME
     std::remove_extent - std::remove_extent

Synopsis
	Defined in header <type_traits>
	template< class T >		 (since C++11)
	struct remove_extent;

	If  T is an array of some type X, provides the member typedef type equal
     to X,
	otherwise type is T. Note that if T is a  multidimensional  array,  only
     the first
	dimension is removed.

	If the program adds specializations for std::remove_extent, the behavior
     is
	undefined.

Member types
	Name Definition
	type the type of the element of T

Helper types
	template< class T >					  (since C++14)
	using remove_extent_t = typename remove_extent<T>::type;

Possible implementation
	template<class T>
	struct remove_extent { using type = T; };

	template<class T>
	struct remove_extent<T[]> { using type = T; };

	template<class T, std::size_t N>
	struct remove_extent<T[N]> { using type = T; };

Example
     // Run this code

      #include <algorithm>
      #include <iostream>
      #include <iterator>
      #include <type_traits>

      template<class A>
	  std::enable_if_t<std::rank_v<A> == 1>
      print_1d(const A& a)
      {
	  std::copy(a, a + std::extent_v<A>,
	      std::ostream_iterator<std::remove_extent_t<A>>(std::cout, " "));
	  std::cout << '\n';
      }

      int main()
      {
	  int a[][3] = {{1, 2, 3}, {4, 5, 6}};
      //  print_1d(a); // compile-time error
	  print_1d(a[1]);
      }

Output:
      4 5 6

See also
	is_array	   checks if a type is an array type
	(C++11) 	   (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_all_extents removes all extents from the given array type
	(C++11) 	   (class template)

http://cppreference.com 	   2024.06.10		   std::remove_extent(3)
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