operator-

operator-

template<class RanIt, class T, class Ref, class Ptr, class Dist>
    Dist operator-(
        const reverse_iterator<RanIt, T, Ref, Ptr, Dist>& lhs,
        const reverse_iterator<RanIt, T, Ref, Ptr, Dist>& rhs);

The template operator returns rhs.current - lhs.current.