std::remove_all_extents - cppreference.com (original) (raw)

| | | | | ------------------------------------------------- | | ------------- | | 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.

[edit] Member types

[edit] Helper types

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

[edit] Possible implementation

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

[edit] Example

#include #include #include   template void info(const A&) { typedef typename std::remove_all_extents::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

[edit] See also

| | checks if a type is an array type (class template) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | obtains the number of dimensions of an array type (class template) [edit] | | | obtains the size of an array type along a specified dimension (class template) [edit] | | | removes one extent from the given array type (class template) [edit] |