25 Iterators library [iterators]

25.5 Iterator adaptors [predef.iterators]

25.5.7 Counted iterators [iterators.counted]

25.5.7.3 Accessors [counted.iter.access]

constexpr const I& base() const & noexcept;
Effects: Equivalent to: return current;
constexpr I base() &&;
Returns: std​::​move(current).
constexpr iter_difference_t<I> count() const noexcept;
Effects: Equivalent to: return length;