27 Iterators library [iterators]

27.5 Iterator adaptors [predef.iterators]

27.5.1 Reverse iterators [reverse.iterators]

27.5.1.3 reverse_­iterator operations [reverse.iter.ops]

27.5.1.3.4 operator* [reverse.iter.op.star]

constexpr reference operator*() const;

Iterator tmp = current;
return *--tmp;