BidirectionalIterator

A BidirectionalIterator is a ForwardIterator that can be moved in both directions (i.e. incremented and decremented).

Requirements

The type It satisfies BidirectionalIterator if.

The type It satisfies ForwardIterator

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: `a` is decrementable (there exists such `b` that `a == ++b`) Postconditions: a is dereferenceable `--(++a) == a` If `--a == --b` then `a == b` `&a == &--a`
`a--`	convertible to `const It&`	`It temp = a; --a; return temp;`
`*a--`	`reference`

A mutable BidirectionalIterator is a BidirectionalIterator that additionally satisfies the OutputIterator requirements.

Notes

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).

BidirectionalIterator

Requirements

Notes

See also