20 General utilities library [utilities]

20.15 Metaprogramming and type traits [meta]

20.15.7 Transformations between types [meta.trans]

20.15.7.4 Array modifications [meta.trans.arr]

Table 55: Array modifications   [tab:meta.trans.arr]
Template
Comments
template<class T>
struct remove_­extent;
If T names a type “array of U”, the member typedef type shall be U, otherwise T.
[ Note
:
For multidimensional arrays, only the first array dimension is removed.
For a type “array of const U”, the resulting type is const U.
— end note
 ]
template<class T>
struct remove_­all_­extents;
If T is “multi-dimensional array of U”, the resulting member typedef type is U, otherwise T.
1
#
[ Example
: 
// the following assertions hold:
assert((is_same_v<remove_extent_t<int>, int>));
assert((is_same_v<remove_extent_t<int[2]>, int>));
assert((is_same_v<remove_extent_t<int[2][3]>, int[3]>));
assert((is_same_v<remove_extent_t<int[][3]>, int[3]>));
— end example
 ]
2
#
[ Example
: 
// the following assertions hold:
assert((is_same_v<remove_all_extents_t<int>, int>));
assert((is_same_v<remove_all_extents_t<int[2]>, int>));
assert((is_same_v<remove_all_extents_t<int[2][3]>, int>));
assert((is_same_v<remove_all_extents_t<int[][3]>, int>));
— end example
 ]