^
   HOME



picture info

Exponentiation
In mathematics, exponentiation, denoted , is an operation (mathematics), operation involving two numbers: the ''base'', , and the ''exponent'' or ''power'', . When is a positive integer, exponentiation corresponds to repeated multiplication of the base: that is, is the product (mathematics), product of multiplying bases: b^n = \underbrace_.In particular, b^1=b. The exponent is usually shown as a superscript to the right of the base as or in computer code as b^n. This binary operation is often read as " to the power "; it may also be referred to as " raised to the th power", "the th power of ", or, most briefly, " to the ". The above definition of b^n immediately implies several properties, in particular the multiplication rule:There are three common notations for multiplication: x\times y is most commonly used for explicit numbers and at a very elementary level; xy is most common when variable (mathematics), variables are used; x\cdot y is used for emphasizing that one ta ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control characters a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers; for example, the first 128 code points of Unicode are the same as ASCII. ASCII encodes each code-point as a value from 0 to 127 storable as a seven-bit integer. Ninety-five code-points are printable, including digits ''0'' to ''9'', lowercase letters ''a'' to ''z'', uppercase letters ''A'' to ''Z'', and commonly used punctuation symbols. For example, the letter is represented as 105 (decimal). Also, ASCII specifies 33 non-printing control codes which originated with ; most of which are now obsolete. The control cha ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Regular Expression
A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation. Regular expression techniques are developed in theoretical computer science and formal language theory. The concept of regular expressions began in the 1950s, when the American mathematician Stephen Cole Kleene formalized the concept of a regular language. They came into common use with Unix text-processing utilities. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, widely used, being the Perl syntax. Regular expressions are used in search engines, in search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK, and in lexical analysis ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

ISO/IEC 646
ISO/IEC 646 ''Information technology — ISO 7-bit coded character set for information interchange'', is an International Organization for Standardization, ISO/International Electrotechnical Commission, IEC standard in the field of character encoding. It is equivalent to the Ecma International, ECMA standard ECMA-6 and developed in cooperation with ASCII at least since 1964. The first version of ECMA-6 had been published in 1965, based on work the ECMA's Technical Committee TC1 had carried out since December 1960. The first edition of ISO/IEC 646 was published in 1973, and the most recent, third, edition in 1991. ISO/IEC 646 specifies a 7-bit character code from which several national standards are derived. It allocates a set of 82 unique graphic characters to 7-bit code points, known as the ''invariant'' (INV) or ''basic character set'', including letters of the ISO basic Latin alphabet, Numerical digit, digits, and some common English language, English pun ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Caret Notation
Caret notation is a notation for control characters in ASCII. The notation assigns to control-code 1, sequentially through the alphabet to assigned to control-code 26 (0x1A). For the control-codes outside of the range 1–26, the notation extends to the adjacent, non-alphabetic ASCII characters. Often a control character can be typed on a keyboard by holding down the and typing the character shown after the caret. The notation is often used to describe keyboard shortcuts even though the control character is not actually used (as in "type ^X to Cut, copy, and paste, cut the text"). The meaning or interpretation of, or response to the individual control-codes is ''not'' prescribed by the caret notation. Description The notation consists of a ''caret (computing), caret'' () followed by a single character (usually a capital letter). The character has the ASCII code equal to the control code with the bit representing 0x40 reversed. A useful mnemonic, this has the eff ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Control Characters
In computing and telecommunications, a control character or non-printing character (NPC) is a code point in a character set that does not represent a written character or symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other characters are mainly '' graphic characters'', also known as ''printing characters'' (or ''printable characters''), except perhaps for "space" characters. In the ASCII standard there are 33 control characters, such as code 7, , which rings a terminal bell. History Procedural signs in Morse code are a form of control character. A form of control characters were introduced in the 1870 Baudot code: NUL and DEL. The 1901 Murray code added the carriage return (CR) and line feed (LF), and other versions of the Baudot code included other control characters. The bell character (BEL), which rang a bell to alert operators, was also an early teletype control character. Some control character ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Control Character
In computing and telecommunications, a control character or non-printing character (NPC) is a code point in a character encoding, character set that does not represent a written Character (computing), character or symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other characters are mainly ''graphic characters'', also known as ''printing characters'' (or ''printable characters''), except perhaps for "space (punctuation), space" characters. In the ASCII standard there are 33 control characters, such as code 7, , which rings a terminal bell. History Prosigns for Morse code, Procedural signs in Morse code are a form of control character. A form of control characters were introduced in the 1870 Baudot code: NUL and DEL. The 1901 Murray code added the carriage return (CR) and line feed (LF), and other versions of the Baudot code included other control characters. The bell character (BEL), which rang a bell to alert op ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Pascal (programming Language)
Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named after French mathematician, philosopher and physicist Blaise Pascal. Pascal was developed on the pattern of the ALGOL 60 language. Wirth was involved in the process to improve the language as part of the ALGOL X efforts and proposed a version named ALGOL W. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970. On top of ALGOL's scalars and arrays, Pascal enables defining complex datatypes and building dynamic and recursive data structures such as lists, trees and graphs. Pascal has strong typing on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit conversions ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

QWERTY
QWERTY ( ) is a keyboard layout for Latin-script alphabets. The name comes from the order of the first six Computer keyboard keys#Types, keys on the top letter row of the keyboard: . The QWERTY design is based on a layout included in the Sholes and Glidden typewriter sold via E. Remington and Sons from 1874. QWERTY became popular with the success of the Remington No. 2 of 1878 and remains in ubiquitous use. History The QWERTY layout was devised and created in the early 1870s by Christopher Latham Sholes, a newspaper editor and printer who lived in Kenosha, Wisconsin. In October 1867, Sholes filed a patent application for his early writing machine he developed with the assistance of his friends Carlos Glidden and Samuel W. Soule, Samuel W. Soulé. The first model constructed by Sholes used a piano-like keyboard with two rows of characters arranged alphabetically as shown below: - 3 5 7 9 N O P Q R S T U V W X Y Z 2 4 6 8 . A B C D E F G H I J K L M Sholes struggled for th ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Dead Key
A dead key is a special kind of modifier key on a mechanical typewriter, or computer keyboard, that is typically used to attach a specific diacritic to a base letter (alphabet), letter. The dead key does not generate a (complete) grapheme, character by itself, but modifies the character generated by the key struck immediately after. Thus, a dedicated key is not needed for each possible combination of a diacritic and a letter, but rather only one dead key for each diacritic is needed, in addition to the normal base letter keys. For example, if a keyboard mapping (such as US international) has a dead key for the circumflex, , the character can be generated by first pressing and then . Usually, the diacritic itself can be generated as a free-standing character by pressing the dead key followed by ''space''; so a caret (free-standing circumflex) can be typed by pressing and then . Mechanical typewriters The dead key is mechanical in origin, and "dead" means without movement. ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Circumflex
The circumflex () is a diacritic in the Latin and Greek scripts that is also used in the written forms of many languages and in various romanization and transcription schemes. It received its English name from "bent around"a translation of the (). The circumflex in the Latin script is chevron-shaped (), while the Greek circumflex may be displayed either like a tilde () or like an inverted breve (). For the most commonly encountered uses of the accent in the Latin alphabet, precomposed characters are available. In English, the circumflex, like other diacritics, is sometimes retained on loanwords that used it in the original language (for example '' entrepôt, crème brûlée''). In mathematics and statistics, the circumflex diacritic is sometimes used to denote a function and is called a '' hat operator''. A free-standing version of the circumflex symbol, , is encoded in ASCII and Unicode and has become known as '' caret'' and has acquired special uses, particularly i ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




C Trigraph
In computer programming, digraphs and trigraphs are sequences of two and three characters, respectively, that appear in source code and, according to a programming language's specification, should be treated as if they were single characters. Various reasons exist for using digraphs and trigraphs: keyboards may not have keys to cover the entire character set of the language, input of special characters may be difficult, text editors may reserve some characters for special use and so on. Trigraphs might also be used for some EBCDIC code pages that lack characters such as . History The basic character set of the C programming language is a subset of the ASCII character set that includes nine characters which lie outside the ISO 646 invariant character set. This can pose a problem for writing source code when the encoding (and possibly keyboard) being used does not support one or more of these nine characters. The ANSI C committee invented trigraphs as a way of entering sourc ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]