Iterator Behaviors

Common to all iterator types

++ i	Advance one element and return a reference to i
i ++	Advance one element and return the previous value of i

Input

* i	Return a read-only reference to the element at i's current position.
i == j	Return true if i and j are both positioned at the same element.
i != j	Return true if i and j are positioned at different elements.

Output

* i	Return a writeable reference to the element at i's current position.
i = j	Set i's position to the same as j's.

Bidirectional

--i	Retreat one element and return i's new value.
i--	Retreat one element and return i's previous value.

Random access

i += n	Advance by n locations and return a reference to i.
i -= n	Retreat by n locations and return a reference to i.
i + n	Return an iterator that is positioned n elements ahead of i's current position.
i - n	Return an iterator that is positioned n elements behind i's current position.
i [ n ]	Return a reference to the n th element from i's current position.

According to this hierarchy of interfaces, a regular C pointer is considered a random access iterator. Therefore, STL algorithms can accept regular C pointers as well as STL iterators. In addition, many proprietary class libraries define iterator objects with the characteristics just described. The STL algorithms can also accept these iterators as arguments.