Regress this iterator to the previous valid data element, and return a reference providing modifiable access to this iterator. If there is no preceding data element, the value of reverse_iterator(*this) will be rend().
reverse_iterator(*this)
rend()
Declared in <bdlt_dayofweekset.h>
<bdlt_dayofweekset.h>
DayOfWeekSet_Iter& operator--();