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bg_25 2006. január 16., 18:37 (CET)
==karakter(számítástechnika)==
{{Lektor}}
''A [[számítástechnia]] és a számítógép alapú [[telekommunikáció]] szóhasználatában a '''karakter''' az [[információ]] egy egysége, (ez nagyjából egybeesik a [[graféma]] értelmezésével) vagy a [[természetes nyelv]] [[írott nyelv]]i formájának egy szimbóluma.''
Például karakter egy betű, [[számjegy|szám]], vagy [[elválasztó]] jel, valamint a [[speciális karakter]]ek, mint például a %,$, @, stb. Megegyezés szerint karaternek számítanak a [[vezérlő karater]]ek, amelyek nincsenek kapcsolatban a természetes nyelvekkel, viszont információt hordoznak a nyomtatt forma feldolgozásánál vagy megjelenítésénél, különösen [[számítógépes nyomtató|nyomtató]]k vagy más egyéb megjelenítők vezérlésénél.
== Character encoding ==
{{main|character encoding}}
Computers and communication equipment represent characters using a [[character encoding]] that assigns each character to something — an [[integer]] quantity represented by a sequence of [[bit]]s, typically — that can be [[computer storage|stored]] or transmitted through a [[computer network|network]]. The most common encoding is [[ASCII]], though the more versatile [[Unicode]] is quickly becoming popular. While most character encodings map characters to numbers and/or bit sequences, [[Morse code]] instead represents characters using a series of electrical impulses of varying length.
== Terminology ==
Historically, the terms ''character'' has been widely used by industry professionals to refer to an ''encoded character'' (often only as exposed via a [[programming language]]'s [[API]]). Likewise, ''character set'' has been widely used to refer to a specific ''repertoire'' of ''abstract characters'' that have been mapped to specific bit sequences. With the advent of Unicode and bit-agnostic ''encoding forms'', more precise terminology is increasingly favored.
It is important, in some contexts, to make the distinction that a character is a unit of ''information'', and thus does not imply any particular physical appearance. For example, the Hebrew letter [[Aleph (letter)|Aleph]] ("א") is often used by mathematicians to denote certain kinds of [[infinity]], but it is also used in ordinary Hebrew text. In Unicode, these two uses are different characters and are signified by two different codes, though they may be rendered identically. Conversely, the Chinese [[logogram]] for water ("水") may have a slightly different appearance in Japanese texts than it does in Chinese texts, and local typefaces may reflect this. But they nonetheless represent the same information, are considered the same character, and share the same Unicode code point.
The term [[glyph]] is used to describe a particular physical appearance of a character. Many computer [[typeface|font]]s consist of glyphs that are indexed by the Unicode code point of the character that each glyph represents.
The definition of ''character'', or ''abstract character'', is mutually defined by The Unicode Standard and [[Universal Character Set|ISO/IEC 10646]] as "a member of a set of elements used for the organisation, control, or representation of data." Unicode's definition supplements this with explanatory notes that encourage the reader to differentiate between characters, graphemes, and glyphs, among other things. The standards also differentiate between these abstract characters and ''coded characters'' or ''encoded characters'' that have been paired with numeric codes that facilitate their representation in computers.
==Lásd még==
* Characters are often combined in [[string (számítástechnika)|string]] vagy jelsorozat.
==External links==
* [http://anubis.dkuug.dk/jtc1/sc2/wg2/docs/tr15285:1998.pdf ISO/IEC TR 15285:1998] summarizes the ISO/IEC's character model, focusing on terminology definitions and differentiating between characters and glyphs
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