Computer programs are Instruction for a computer. A computer requires programs to function. Moreover, a computer program does not run unless its instructions are executed by a Central processing unit; however, a program may communicate an Algorithm#Formalization of algorithms to people without running.... that prints out "Hello world!" on a display device
Display device
A display device is an output device for presentation of information for visual, tactile or Hearing_ reception, acquired, stored, or transmitted in various forms.... . It is used in many introductory tutorials for teaching a programming language
Programming language
A programming language is a machine-readable artificial language designed to express computations that can be performed by a machine, particularly a computer.... . Such a program is typically one of the simplest programs possible in a computer language. Some are surprisingly complex, especially in some graphical user interface
Graphical user interface
A graphical user interface is a type of user interface which allows people to human-computer interaction such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment.... (GUI) contexts, but most are very simple, especially those which rely heavily on a particular command line interpreter
Command line interpreter
A command-line interpreter is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language.... ("shell") to perform the actual output.
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Computer programs are Instruction for a computer. A computer requires programs to function. Moreover, a computer program does not run unless its instructions are executed by a Central processing unit; however, a program may communicate an Algorithm#Formalization of algorithms to people without running.... that prints out "Hello world!" on a display device
Display device
A display device is an output device for presentation of information for visual, tactile or Hearing_ reception, acquired, stored, or transmitted in various forms.... . It is used in many introductory tutorials for teaching a programming language
Programming language
A programming language is a machine-readable artificial language designed to express computations that can be performed by a machine, particularly a computer.... . Such a program is typically one of the simplest programs possible in a computer language. Some are surprisingly complex, especially in some graphical user interface
Graphical user interface
A graphical user interface is a type of user interface which allows people to human-computer interaction such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment.... (GUI) contexts, but most are very simple, especially those which rely heavily on a particular command line interpreter
Command line interpreter
A command-line interpreter is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language.... ("shell") to perform the actual output. In many embedded system
Embedded system
An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions, often with real-time computing constraints.... s, the text may be sent to a one or two-line liquid crystal display
Liquid crystal display
A liquid crystal display is an Electro-optic modulator shaped into a thin, flat panel made up of any number of color or monochrome pixels filled with liquid crystals and arrayed in front of a Light#Light sources or reflector.... (LCD), or some other appropriate signal, such as a LED
Light-emitting diode
A light-emitting diode , is an electronic light source. The LED was discovered in the early 20th century, and introduced as a practical electronic component in 1962.... being turned on, may substitute for the message.
Purpose
A "hello world" program has become the traditional first program that many people learn. In general, it is simple enough that people who have no previous experience with computer programming can easily understand it, especially with the guidance of a teacher or a written guide. Using this simple program as a basis, computer science
Computer science
Computer science is the study of the theoretical foundations of information and computation, and of practical techniques for their implementation and application in computer systems.... principles or elements of a specific programming language
Programming language
A programming language is a machine-readable artificial language designed to express computations that can be performed by a machine, particularly a computer.... can be explained to novice programmers. Experienced programmers learning new languages can also gain a lot of information about a given language's syntax and structure from a hello world program.
In addition, hello world can be a useful sanity test
Sanity test
A sanity test or sanity check is a basic test to quickly evaluate the validity of a claim or calculation. In mathematics, for example, when multiplying by three or nine, verifying that the sum of digits, in the result, is a multiple of 3 or 9 , respectively, is a sanity test.... to make sure that a language's compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language . The most common reason for wanting to transform source code is to create an executable program.... , development environment
Development environment
Development environment may refer to Integrated development environment.In hosted software development, Development environment refers to an server tier designated to a specific stage in a release process.... , and run-time environment are correctly installed. Configuring a complete programming toolchain
Toolchain
In software, a toolchain is the set of computer programs that are used to create a product . The tools may be used in a chain, so that the output of each tool becomes the input for the next, but the term is used widely to refer to any set of linked development tools.... from scratch to the point where even trivial programs can be compiled and run can involve substantial amounts of work. For this reason, a simple program is used first when testing a new tool chain.
"Hello world" is also used by computer hackers as a proof of concept that arbitrary code can be executed through an exploit
Exploit (computer security)
An exploit is a piece of software, a chunk of data, or sequence of commands that take advantage of a software bug, glitch or vulnerability in order to cause unintended or unanticipated behavior to occur on computer software, hardware, or something electronic .... where code should not be allowed to be executed, for example, on Sony's Playstation Portable
PlayStation Portable
The PlayStation Portable is a handheld game console manufactured and marketed by Sony Computer Entertainment. Development of the console was first announced during History of E3#During the Rise of Online Gaming , and it was unveiled on May 11, 2004 at a Sony press conference before E3 2004.... . This is the first step into making home-made content ("homebrew
Homebrew (video games)
Homebrew is a term frequently applied to video games produced by consumers to target proprietary hardware platforms not typically user-programmable or that use proprietary storage methods.... ") usable on such a device.
History
While small test programs existed since the development of programmable computer
Computer
A computer is a machine that manipulates Data according to a list of Code .The first devices that resemble modern computers date to the mid-20th century , although the computer concept and various machines similar to computers existed earlier.... s, the tradition of using the phrase "Hello world!" as a test message was influenced by an example program in the seminal book The C Programming Language
The C Programming Language (book)
The C Programming Language is a well-known computer science book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language .... . The example program from that book prints "hello, world" (without capital letters or exclamation mark), and was inherited from a 1974 Bell Laboratories
Bell Labs
Bell Laboratories is the research organization of Alcatel-Lucent and previously of the American Telephone & Telegraph Company .Bell Laboratories has had its headquarters at Berkeley Heights, New Jersey, and it has research and development facilities throughout the world.... internal memorandum by Brian Kernighan
Brian Kernighan
Brian Wilson Kernighan , is a computer scientist who worked at Bell Labs alongside Unix creators Ken Thompson and Dennis Ritchie and contributed greatly to Unix and its school of thought.... , Programming in C: A Tutorial, which contains the first known version:
main
The first known instance of the usage of the words "hello" and "world" together in computer literature occurred earlier, in Kernighan's 1972 Tutorial Introduction to the Language B, with the following code:
main
a 'hell';
b 'o, w';
c 'orld';
Variations
There are many variations on the punctuation and casing of the phrase. Variations include the presence or absence of the comma and exclamation mark, and the capitalization of the 'H', both the 'H' and the 'W', or neither. Some languages are forced to implement different forms, such as "HELLO WORLD!", on systems that only support capital letters, while many "hello world" programs in esoteric languages
Esoteric programming language
An esoteric programming language is a programming language designed as a test of the boundaries of computer programming language design, as a proof of concept, or as a joke.... print out a slightly modified string. For example, the first non-trivial Malbolge
Malbolge
Malbolge is a public domain esoteric programming language invented by Ben Olmstead in 1998, named after the eighth circle of hell in Dante Alighieri's The Divine Comedy, the Malebolge.... program printed "HEllO WORld", this having been determined to be "good enough".
In computer science, functional programming is a programming paradigm that treats computation as the evaluation of function s and avoids program state and immutable object data.... languages, like ML, and Haskell
Haskell (programming language)
Haskell is a standardized, purely functional programming language with non-strict programming language, named after logician Haskell Curry. The goals of the language are described as:... , tend to substitute a factorial
Factorial
In mathematics, the factorial of a negative and non-negative numbers integer n, denoted by n!, is the Product of all positive integers less than or equal to n.... program for Hello World, as the former emphasizes recursive techniques, which are a big part of functional programming, while the latter emphasizes I/O, which violates the spirit of pure functional programming by producing side effects.
DebianGNU/Linux is one of the most popular and influential computer operating systems composed of free software and open source software.... and Ubuntu Linux
Linux
Linux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed by anyone under the terms of the GNU GPL license... distributions provide the "hello world" program through the apt
Advanced Packaging Tool
The Advanced Packaging Tool, or APT, is a Free software front-end that works with Software Library to handle the installation and removal of software on the Debian GNU/Linux computer operating system and its variants.... packaging system; this allows users to simply type "apt-get install hello" for the program to be installed, along with any software dependencies. While seemingly useless, the hello package serves as a simple example Debian package for newcomers to learn from -- and in fact, the version of hello used, GNU
GNU
GNU is a computer operating system composed entirely of free software. Its name is a recursive acronym for GNU's Not Unix; it was chosen because its design is Unix-like, but differs from Unix by being free software and containing no Unix code.... hello, serves a similar purpose itself as an example of how to write a GNU program.
The Trabb Pardo-Knuth algorithm is a computer program introduced by Donald Knuth and Luis Trabb Pardo to illustrate the evolution of computer programming languages....
Just another Perl hacker, or JAPH, typically refers to a Perl program which prints "Just another Perl hacker," . Short JAPH programs are often used as signature block in online Internet forum, or as T-shirt designs....
Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems....
