The
random_access_iterator concept adds support for
constant-time advancement with
+=,
+,
-=, and
-,
as well as the computation of distance in constant time with
-.Random access iterators also support array notation via subscripting
.
template<class I>
concept random_access_iterator =
bidirectional_iterator<I> &&
derived_from<ITER_CONCEPT(I), random_access_iterator_tag> &&
totally_ordered<I> &&
sized_sentinel_for<I, I> &&
requires(I i, const I j, const iter_difference_t<I> n) {
{ i += n } -> same_as<I&>;
{ j + n } -> same_as<I>;
{ n + j } -> same_as<I>;
{ i -= n } -> same_as<I&>;
{ j - n } -> same_as<I>;
{ j[n] } -> same_as<iter_reference_t<I>>;
};