Editing Theoretical computer science (section)

===Data structures===
{{main|Data structure}}
A [[data structure]] is a particular way of organizing [[data (computing)|data]] in a computer so that it can be used [[algorithmic efficiency|efficiently]].<ref>Paul E. Black (ed.), entry for ''data structure'' in ''[[Dictionary of Algorithms and Data Structures]]. U.S. [[National Institute of Standards and Technology]]. 15 December 2004. [http://xlinux.nist.gov/dads/HTML/datastructur.html Online version] Accessed May 21, 2009.''</ref><ref>Entry ''data structure'' in the [[Encyclopædia Britannica]] (2009) [http://www.britannica.com/EBchecked/topic/152190/data-structure Online entry] accessed on May 21, 2009.</ref>

Different kinds of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks. For example, databases use [[B-tree]] indexes for small percentages of data retrieval and [[compiler]]s and databases use dynamic [[hash table]]s as look up tables.

Data structures provide a means to manage large amounts of data efficiently for uses such as large [[database]]s and [[web indexing|internet indexing services]]. Usually, efficient data structures are key to designing efficient [[algorithm]]s. Some formal design methods and [[programming language]]s emphasize data structures, rather than algorithms, as the key organizing factor in software design. Storing and retrieving can be carried out on data stored in both [[main memory]] and in [[secondary memory]].