Iterator
The Iterator design pattern introduces an external object that allows to go through the items of collections without knowing the internal structure of the collections. This is one of the most popular pattern, and you can find it implemented in standard libraries of almost all programming languages. Sometimes, it's called Enumerator instead of Iterator.
Motivation
Today's programming languages often provide rich variety of collections,
i.e., arrays, lists, dictionaries (hashmap), but also e.g. trees. Sometimes,
it's useful to implement our own collection, especially if it's supposed to
provide some special operations over its elements. At some point, we need to
iterate through every collection, i.e. to go through all its elements from the
first to the last one and print them, for example. If each collection
implemented its own interface to iterate over its elements, first, we'd have to
examine them, and collections are sometimes really complicated. And second, the
language itself won't be able to support syntactic sugar such as the
foreach loop. If you think of introducing some general interface
the
...End of the preview...
Premium article
ict.social is a large database made up of manuals and tutorials, whose main goal is to provide high-quality IT education to everyone. We started out in the Czech republic, where we display roughly a million articles per month and receive plenty of gratitude from our users. Thanks to our successful establishment, we are now bringing these articles to the rest of the world.
Although we are trying to keep our content free of charge, maintaining the site is a huge effort for everyone involved. Therefore, some content (exercises and more advanced material) costs network points. Don't worry, they're really cheap :)
Article description
Requested article covers this content:
The Iterator design pattern introduces an external object that allows to go through a collection linearly without having to know its internal structure.
Buying this article gives you unlimited access to it forever. You will learn some more and help us keep giving our site maintenance which helps you and others get better futures. It's a win-win.
This article is licensed :Premium, by buying this article, you agree with the terms of use.
You gain points by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.
You can get points immediately using:
 |
 |
 |
| Credit card | SMS | Wire transfer |
The author learned IT at the Unicorn College - a prestigious college providing education on IT and economics. 