CASPIAN JOURNAL
MANAGEMENT AND HIGH TECHNOLOGIES
DEMONSTRATION OF INFORMATION RETRIEVAL USING HASHING
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Read | Smirnova Marina O. DEMONSTRATION OF INFORMATION RETRIEVAL USING HASHING // Caspian journal : management and high technologies. — 2011. — №3. — pp. 25-30. |
Smirnova Marina O. - Cand. in Pedag., Astrakhan State University, 20a Tatishchev str., Astrakhan, 414056, Russia, apsmir@yandex.ru.
This article presents a software product that demonstrates the application of hashing, which is the corresponding fast-method of software search. Hashing is used in working with large data sets (browsers, dictionaries, compilers, etc.) and in cryptography. A description of the main components of the software, implemented in the programming language Object Pascal in a visual programming environment, Delphi 7, and the possibilities for the study of topics related to search algorithms that are based on hash tables are given. The modeling of the process of finding information using hash tables in this software product is implemented on the building of the phone directory with using a table for indoor and outdoor addressing, as examples of open and closed hashing. Data types on which the implementation of algorithms is realised, are arrays and records designed to store both data and keys for them. In the addition this first type of hash is based on the relationship between the array and the singly-linked lists. Singly-linked lists are implemented using pointers to records. Each key stored in the array corresponds to a pointer to its list of the data. The second type of hash is based entirely on the use of the array, that presumably, has more elements than the possible amount of data, and is closed in a ring. The software product is provided with help system, which allows to get acquainted with the basis of hashing and principles of the program. The software product provides the support of topics that are related to algorithms of search based on hash tables with visual materials.
Key words: demonstration program,hashing,searching for information,program code,singly-linked lists,array,record,key,pointer,data types.