24 Iterators library [iterators]

24.5 Iterator adaptors [predef.iterators]

24.5.1 Reverse iterators [reverse.iterators]

24.5.1.3 reverse_iterator operations [reverse.iter.ops]

24.5.1.3.19 operator- [reverse.iter.opdiff]

template <class Iterator1, class Iterator2> auto operator-( const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y) -> decltype(y.base() - x.base());

1

Returns: y.current - x.current.