A LegacyBidirectionalIterator is a LegacyForwardIterator that can be moved in both directions (i.e. incremented and decremented).
The type It
satisfies LegacyBidirectionalIterator if.
It
satisfies LegacyForwardIterator And, given.
a
and b
, iterators of type It
reference,
the type denoted by std::iterator_traits<It>::reference
The following expressions must be valid and have their specified effects.
Expression | Return | Equivalent expression | Notes |
---|---|---|---|
--a | It& | Preconditions:
Postconditions:
|
|
a-- | convertible to const It&
|
It temp = a; --a; return temp; | |
*a-- | reference |
A mutable LegacyBidirectionalIterator is a LegacyBidirectionalIterator that additionally satisfies the LegacyOutputIterator requirements.
The begin iterator is not decrementable and the behavior is undefined if --container.begin()
is evaluated.
A bidirectional iterator does not have to be dereferenceable to be decrementable (in particular, the end iterator is not dereferenceable but is decrementable).
ConceptFor the definition of
where the exposition-only concept | (since C++20) |
specifies that a ForwardIterator is a bidirectional iterator, supporting movement backwards (concept) |
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