C++

Reference

<type_traits>

class template
<type_traits>

std::remove_extent

template <class T> struct remove_extent;
Remove array extent
Obtains the type of the elements in T (if T is an array type).

The transformed type is aliased as member type remove_extent::type.

If T is an array type, this is the same type as its elements. Otherwise, member type is the same as T.

Notice that, for multidimensional arrays, only the first array dimension is removed (see remove_all_extents to obtain the type of the elements in the deepest dimension).

This class merely obtains a type using another type as model, but it does not transform values or objects between those types.

Template parameters

T
A type.

Member types

member typedefinition
typeIf T is an array, the type of the elements in T.
Otherwise, T

Example

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// remove_extent
#include <iostream>
#include <type_traits>

int main() {
  typedef std::remove_extent<int>::type A;                // int
  typedef std::remove_extent<int[24]>::type B;            // int
  typedef std::remove_extent<int[24][60]>::type C;        // int[60]
  typedef std::remove_extent<int[][60]>::type D;          // int[60]

  std::cout << std::boolalpha;
  std::cout << "typedefs of int:" << std::endl;
  std::cout << "A: " << std::is_same<int,A>::value << std::endl;
  std::cout << "B: " << std::is_same<int,B>::value << std::endl;
  std::cout << "C: " << std::is_same<int,C>::value << std::endl;
  std::cout << "D: " << std::is_same<int,D>::value << std::endl;

  return 0;
}

Output:
typedefs of int:
A: true
B: true
C: false
D: false


See also

remove_all_extents
Remove all array extents (class template)
extent
Array dimension extent (class template)
rank
Array rank (class template)