The Iterator concept describes types that can be used to identify and traverse the elements of a container.
Iterator is the base concept used by other iterator types: InputIterator, OutputIterator, ForwardIterator, BidirectionalIterator, and RandomAccessIterator. Iterators can be thought of as an abstraction of pointers.
Requirements
The type It satisfies Iterator if
Given
The following expressions must be valid and have their specified effects:
| Expression |
Return Type |
Precondition
|
| *r
|
unspecified
|
r is dereferenceable (see below)
|
| ++r
|
It&
|
r is incrementable (the behavior of the expression ++r is defined)
|
Dereferenceable iterators
Iterators for which the behavior of the expression *i is defined are called dereferenceable.
Iterators are not dereferenceable if
- they are past-the-end iterators (including pointers past the end of an array) or before-begin iterators. Such iterators may be dereferenceable in a particular implementation, but the library never assumes that they are.
- they are singular iterators, that is, iterators that are not associated with any sequence. A null pointer, as well as a default-constructed pointer (holding an indeterminate value) is singular
- they were invalidated by one of the iterator-invalidating operations on the sequence to which they refer.
See also
|
|
specifies that objects of a type can be incremented and dereferenced
(concept) |