Re: reverse-iterator for LinkedList

Lew <>
Wed, 13 Feb 2008 19:06:45 -0500
Eric Sosman wrote:

Andreas Leitgeb wrote:

In some app of mine I've got a LinkedList of items. Now,
I want to check the last couple of items for some condition.
In practice I expect the list to be about 30 elements
long, and only the last three elements to be actually
visited. Oh and the context is somewhat time-critical.

Now, I think that an Iterator (actually ListIterator) would be
appropriate for my task, but the only way to get one seems to be
through method listIterator(int index). I can't help, but passing
in the lists size for the index feels like it would search forward
completely through the list to obtain an iterator that starts
from end.

    "Use the source, Andreas," and you'll find that LinkedList
initializes its ListIterator by searching from the nearer end.

"Use the Javadocs" is better advice - you get the answer in the documentation
for the class:

Operations that index into the list will traverse the list from the beginning
or the end, whichever is closer to the specified index.


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