"Hello, World!" program

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"Hello, World" redirects here. For other uses, see Hello World (disambiguation).

A "Hello, World!" program is generally a simple

compile or run source code
is correctly installed, and that its operator understands how to use it.

History

C language and signed by Brian Kernighan
(1978)

While small test programs have existed since the development of programmable computers, the tradition of using the phrase "Hello, World!" as a test message was influenced by an example program in the 1978 book The C Programming Language,[2] with likely earlier use in BCPL. The example program from the book prints "hello, world", and was inherited from a 1974 Bell Laboratories internal memorandum by Brian Kernighan, Programming in C: A Tutorial:[3] 

main( ) {
        printf("hello, world");
}

In the above example, the main( )

function defines where the program should start executing. The function body consists of a single statement, a call to the printf() function, which stands for "print formatted"; it outputs to the console whatever is passed to it as the parameter, in this case the string
"hello, world".

The C-language version was preceded by Kernighan's own 1972 A Tutorial Introduction to the Language B,[4] where the first known version of the program is found in an example used to illustrate external variables: 

main( ) {
    extern a, b, c;
    putchar(a); putchar(b); putchar(c); putchar('!*n');
}
 
a 'hell';
b 'o, w';
c 'orld';

The program above prints hello, world! on the terminal, including a newline character. The phrase is divided into multiple variables because in B a character constant is limited to four ASCII characters. The previous example in the tutorial printed hi! on the terminal, and the phrase hello, world! was introduced as a slightly longer greeting that required several character constants for its expression.

The Jargon File reports that "hello, world" instead originated in 1967 with the language BCPL.[5] Outside computing, use of the exact phrase began over a decade prior; it was the catchphrase of New York radio disc jockey William B. Williams beginning in the 1950s.[6]

Variations

A "Hello, World!" program running on Sony's PlayStation Portable as a proof of concept

"Hello, World!" programs vary in complexity between different languages. In some languages, particularly

standard output stream
.

Perspex

The phrase "Hello, World!" has seen various deviations in casing and punctuation, such as the capitalization of the leading H and W, and the presence of the comma or exclamation mark. Some devices limit the format to specific variations, such as all-capitalized versions on systems that support only capital letters, while some

Go programming language outputted both English and Chinese or Japanese characters, demonstrating the programming language's built-in Unicode support.[9] Another notable example is the Rust programming language
, whose management system automatically inserts a "Hello, World" program when creating new projects.

LEDs

Some languages change the functionality of the "Hello, World!" program while maintaining the spirit of demonstrating a simple example.

field-programmable gate arrays, and CPLDs, "Hello, World!" may thus be substituted with a blinking LED, which demonstrates timing and interaction between components.[10][11][12][13][14]

The

.deb package, either traditionally or using debhelper, and the version of hello used, GNU Hello, serves as an example of writing a GNU program.[15]

Variations of the "Hello, World!" program that produce a

XL programming language features a spinning Earth "Hello, World!" using 3D computer graphics.[17] Mark Guzdial and Elliot Soloway have suggested that the "hello, world" test message may be outdated now that graphics and sound can be manipulated as easily as text.[18]

Time to Hello World

"Time to hello world" (TTHW) is the time it takes to author a "Hello, World!" program in a given programming language. This is one measure of a programming language's ease of use; since the program is meant as an introduction for people unfamiliar with the language, a more complex "Hello, World!" program may indicate that the programming language is less approachable.

APIs, as a measure of how simple it is for a new developer to get a basic example working; a shorter time indicates an easier API for developers to adopt.[20][21]

Wikipedia articles containing "Hello, World!" programs

See also

References

  1. ISBN 9781118887820
    .
  2. ISBN 0-13-110163-3
    .
  3. ^ Kernighan, Brian (1974). "Programming in C: A Tutorial" (PDF). Bell Labs. Retrieved 9 January 2019.
  4. ^ "The Programming Language B". Bell Labs.
  5. ^ "BCPL". Jargon File.
  6. ^ "William B. Williams, Radio Personality, Dies". The New York Times. 4 August 1986.
  7. ^ "C++ Programming/Examples/Hello world". Wikibooks. Retrieved 16 March 2022.
  8. ^ "Malbolge". Esolang. esolangs-wiki. Retrieved 28 October 2016.
  9. ^ A Tutorial for the Go Programming Language. Archived 26 July 2010 at the Wayback Machine The Go Programming Language. Retrieved 26 July 2011.
  10. ^ Silva, Mike (11 September 2013). "Introduction to Microcontrollers - Hello World". EmbeddedRelated.com. Retrieved 19 May 2015.
  11. ^ George, Ligo (8 May 2013). "Blinking LED using Atmega32 Microcontroller and Atmel Studio". electroSome. Retrieved 19 May 2015.
  12. ^ PT, Ranjeeth. "2. AVR Microcontrollers in Linux HOWTO". The Linux Documentation Project. Retrieved 19 May 2015.
  13. ^ Andersson, Sven-Åke (2 April 2012). "3.2 The first Altera FPGA design". Raidió Teilifís Éireann. Archived from the original on 21 May 2015. Retrieved 19 May 2015.
  14. ^ Fabio, Adam (6 April 2014). "CPLD Tutorial: Learn programmable logic the easy way". Hackaday. Retrieved 19 May 2015.
  15. ^ "Hello". GNU Project. Free Software Foundation. Archived from the original on 29 May 2014. Retrieved 7 July 2017.
  16. ^ Jolif, Christophe (January 2003). "Bringing SVG Power to Java Applications". Sun Developer Network.
  17. ^ de Dinechin, Christophe (24 July 2010). "Hello world!". Grenouille Bouillie.
  18. ^ "Teaching the Nintendo Generation to Program" (PDF). bfoit.org. Archived from the original (PDF) on 5 May 2016. Retrieved 27 December 2015.
  19. ISBN 978-1-78728-823-2
    . Retrieved 4 December 2019.
  20. ^ Wiegers, Harold (28 June 2018). "The importance of "Time to First Hello, World!" an efficient API program".
  21. ISBN 9781492026877
    . Retrieved 19 February 2020.

External links

Wikimedia Commons has media related to Hello World.
The Wikibook Computer Programming has a page on the topic of: Hello world
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