Regress this iterator to the previous element.
Declared in <bslstl_bidirectionaliterator.h>
BidirectionalIterator<T, ITER_IMP, TAG_TYPE>&
operator--();
Decrement to the previous element. Return a reference to this modifiable iterator. The behavior is undefined if, on entry, this iterator has the same value as an iterator the refers to the start of the underlying sequence.
reference to this modifiable iterator