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In computer science, a literal is a textual representation (notation) of a value as it is written in source code. [1] [2] Almost all programming languages have notations for atomic values such as integers, floating-point numbers, and strings, and usually for Booleans and characters; some also have notations for elements of enumerated types and compound values such as arrays, records, and objects.
A string literal or anonymous string is a literal for a string value in the source code of a computer program. Modern programming languages commonly use a quoted sequence of characters, formally "bracketed delimiters", as in x = "foo", where , "foo" is a string literal with value foo. Methods such as escape sequences can be used to avoid the ...
In the program's source code, this message would likely appear as a string literal. User-entered text, like "I got a new job today" as a status update on a social media service. Instead of a string literal, the software would likely store this string in a database. Alphabetical data, like "AGATGCCGT" representing nucleic acid sequences of DNA. [3]
To modify the first example to shuffle a Tarot deck, which has 78 cards, a programmer might naively replace every instance of 52 in the program with 78. This would cause two problems. First, it would miss the value 53 on the second line of the example, which would cause the algorithm to fail in a subtle way.
Constants are usually defined by enum types or constant parameters that are also written this way. Class and other object type declarations are UpperCamelCase . As of Swift 3.0 there have been made clear naming guidelines for the language in an effort to standardise the API naming and declaration conventions across all third party APIs.
The most significant are: compile-time (statically valued) constants, run-time (dynamically valued) constants, immutable objects, and constant types . Typical examples of compile-time constants include mathematical constants, values from standards (here maximum transmission unit), or internal configuration values (here characters per line ...
Many languages have a syntax specifically intended for strings with multiple lines. In some of these languages, this syntax is a here document or "heredoc": A token representing the string is put in the middle of a line of code, but the code continues after the starting token and the string's content doesn't appear until the next line. In other ...
If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8 , UTF-16 or Shift-JIS , it can be necessary to remove string positions at the end, in order to avoid invalid strings.