Foward iterators

[Dave]

Can anybody offer a specific example of an iterator that has the
capabilities of a forward iterator but no more?

 

[Andrew Koenig]

Can anybody offer a specific example of an iterator that has the
capabilities of a forward iterator but no more?

Look at the sequence class in chapter 15 of "Ruminations on C++."

That class offers behavior similar to Lisp lists, but with the restriction
that all elements of a sequence must have the same type. It also has the
interesting property that the container and iterator classes are the same
type.

 

[Howard Hinnant]

Can anybody offer a specific example of an iterator that has the
capabilities of a forward iterator but no more?

The iterators of a singly linked list are such an example. You can't
iterate backwards (in constant time).

-Howard

 

[Andre Kostur]

The iterators of a singly linked list are such an example. You can't
iterate backwards (in constant time).

-Howard

Or an istream iterator....

 

[Howard Hinnant]

Or an istream iterator....

Actually not really, at least if we're using the std::definition of
"forward". A std::istream_iterator fails to meet the forward spec
because it can not be used in multi-pass algorithms. The standard terms
iterators in this class as "input iterators" which have a subset of the
functionality of forward iterators.

-Howard