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In computer science, a data structure is a particular way of organizing data in a computer so that it can be used efficiently.〔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. (Online version ) Accessed May 21, 2009.''〕〔Entry ''data structure'' in the Encyclopædia Britannica (2009) (Online entry ) accessed on May 21, 2009.〕 Data structures can implement one or more particular abstract data types (ADT), which are the means of specifying the contract of operations and their complexity. In comparison, a data structure is a concrete implementation of the contract provided by an ADT. 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 compilers and databases use dynamic hash tables as look-up tables. Data structures provide a means to manage large amounts of data efficiently for uses such as large databases and internet indexing services. Usually, efficient data structures are key to designing efficient algorithms. Some formal design methods and programming languages 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. ==Overview== Data structures are generally based on the ability of a computer to fetch and store data at any place in its memory, specified by a pointer—a bit string, representing a memory address, that can be itself stored in memory and manipulated by the program. Thus, the array and record data structures are based on computing the addresses of data items with arithmetic operations; while the linked data structures are based on storing addresses of data items within the structure itself. Many data structures use both principles, sometimes combined in non-trivial ways (as in XOR linking). The implementation of a data structure usually requires writing a set of procedures that create and manipulate instances of that structure. The efficiency of a data structure cannot be analyzed separately from those operations. This observation motivates the theoretical concept of an abstract data type, a data structure that is defined indirectly by the operations that may be performed on it, and the mathematical properties of those operations (including their space and time cost). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「data structure」の詳細全文を読む スポンサード リンク
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