std::remove_all_extents

 

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

If T is a multidimensional array of some type X, provides the member typedef type equal to X, otherwise type is T.

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

Member types

Name	Definition
type	the type of the element of T

Helper types

template<class T > using remove_all_extents_t =typename remove_all_extents<T>::type;		(since C++14)

Possible implementation

template<class T>struct remove_all_extents {typedef T type;};   template<class T>struct remove_all_extents<T[]>{typedeftypename remove_all_extents<T>::type type;};   template<class T, std::size_t N>struct remove_all_extents<T[N]>{typedeftypename remove_all_extents<T>::type type;};

Example

Run this code

#include <iostream>#include <type_traits>#include <typeinfo>   template<class A>void info(const A&){typedeftypename std::remove_all_extents<A>::type Type;std::cout<<"underlying type: "<<typeid(Type).name()<<'\n';}   int main(){float a0;float a1[1][2][3];float a2[1][1][1][1][2];float* a3;int a4[3][2];double a5[2][3];struct X {int m;} x0[3][3];   info(a0); info(a1); info(a2); info(a3); info(a4); info(a5); info(x0);}

Possible output:

underlying type: float underlying type: float underlying type: float underlying type: float* underlying type: int underlying type: double underlying type: main::X

See also

is_array (C++11)	checks if a type is an array type (class template)
rank (C++11)	obtains the number of dimensions of an array type (class template)
extent (C++11)	obtains the size of an array type along a specified dimension (class template)
remove_extent (C++11)	removes one extent from the given array type (class template)