mobilleft.blogg.se - Element definition computer science

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ELEMENT DEFINITION COMPUTER SCIENCE SOFTWARE
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Sammet, "the first realistic string handling and pattern matching language" for computers was COMIT in the 1950s, followed by the SNOBOL language of the early 1960s. That a system should consist of 'marks' instead of sounds or odours is immaterial.Īccording to Jean E. Lewis wrote in 1918: Ī mathematical system is any set of strings of recognisable marks in which some of the strings are taken initially and the remainder derived from these by operations performed according to rules which are independent of any meaning assigned to the marks. Use of the word "string" to mean "a sequence of symbols or linguistic elements in a definite order" emerged from mathematics, symbolic logic, and linguistic theory to speak about the formal behavior of symbolic systems, setting aside the symbols' meaning. In 19th-Century typesetting, compositors used the term "string" to denote a length of type printed on paper the string would be measured to determine the compositor's pay.

ELEMENT DEFINITION COMPUTER SCIENCE SERIES

Use of the word "string" to mean any items arranged in a line, series or succession dates back centuries. The term string may also designate a sequence of data or computer records other than characters - like a "string of bits" - but when used without qualification it refers to strings of characters. Often these are intended to be somewhat human-readable, though their primary purpose is to communicate to computers.

Computer settings or parameters, like " ?action=edit" as a URL query string.

Alphabetical data, like " AGATGCCGT" representing nucleic acid sequences of DNA.

ELEMENT DEFINITION COMPUTER SCIENCE SOFTWARE

Instead of a string literal, the software would likely store this string in a database.

ELEMENT DEFINITION COMPUTER SCIENCE UPDATE

User-entered text, like " I got a new job today" as a status update on a social media service.

In the program's source code, this message would likely appear as a string literal.

A message like " file upload complete" is a string that software shows to end users.

Further, strings may store data expressed as characters yet not intended for human reading. A program may also accept string input from its user. Strings are used to communicate information from a computer program to the user of the program. In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set called an alphabet.Ī primary purpose of strings is to store human-readable text, like words and sentences. When a string appears literally in source code, it is known as a string literal or an anonymous string. String may also denote more general arrays or other sequence (or list) data types and structures.ĭepending on the programming language and precise data type used, a variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements.

A string is generally considered as a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. Strings are typically made up of characters, and are often used to store human-readable data, such as words or sentences.