Bidirectional iterator category
Bidirectional iterators are iterators especially designed for sequential access in both directions - towards the end and towards the beginning.
They have the following characteristics:
| characteristic | valid expressions |
|---|
| Can be default-constructed | X a;
X() |
| Can be copied and copy-constructed | X b(a);
b = a; |
Accepts equality/inequality comparisons.
Equal iterators imply the same element is pointed | a == b
a != b |
| Can be dereferenced (when not null) | *a
a->m |
| Can be incremented (when not null) | ++a
a++
*a++ |
| Can be decremented (when not null) | --a
a--
*a-- |
Where X is an iterator type, and a and b are objects of this iterator type.
These characteristics are the same of forward iterators, except that bidirectional iterators also support the decrement operator.
See also
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