Computer programming: Difference between revisions

'''Computer programming''' or '''coding''' is the composition of sequences of instructions, called [[computer program|programs]], that [[computer]]s can follow to perform tasks.<ref>{{cite web|url=http://yearofcodes.tumblr.com/what-is-coding|title=What is coding|last=Bebbington|first=Shaun|year=2014|website=Tumblr|url-status=live|archive-url=https://web.archive.org/web/20200429195646/https://yearofcodes.tumblr.com/what-is-coding|archive-date=2020-04-29|access-date=2014-03-03}}</ref><ref>{{cite web|url=http://yearofcodes.tumblr.com/what-is-programming|title=What is programming|last=Bebbington|first=Shaun|year=2014|website=Tumblr|url-status=live|archive-url=https://web.archive.org/web/20200429195958/https://yearofcodes.tumblr.com/what-is-programming|archive-date=2020-04-29|access-date=2014-03-03}}</ref> It involves designing and implementing [[algorithm]]s, step-by-step specifications of procedures, by writing [[source code|code]] in one or more [[programming language]]s. Programmers typically use [[high-level programming language]]s that are more easily intelligible to humans than [[machine code]], which is directly executed by the [[central processing unit]]. Proficient programming usually requires expertise in several different subjects, including knowledge of the [[Domain (software engineering)|application domain]], details of programming languages and generic code [[library (computing)|libraries]], specialized algorithms, and [[Logic#Formal logic|formal logic]].

Auxiliary tasks accompanying and related to programming include [[Requirements analysis|analyzing requirements]], [[Software testing|testing]], [[debugging]] (investigating and fixing problems), implementation of [[Build automation|build systems]], and management of derived [[Artifact (software development)|artifacts]], such as programs' [[machine code]]. While these are sometimes considered programming, often the term ''[[software development]]'' is used for this larger overall process – with the terms ''programming'', ''implementation'', and ''coding'' reserved for the writing and editing of code per se. Sometimes software development is known as ''[[software engineering]]'', especially when it employs [[formal methods]] or follows an [[engineering design process]].

The first [[computer program]] is generally dated to 1843 when mathematician [[Ada Lovelace]] published an [[algorithm]] to calculate a sequence of [[Bernoulli numbers]], intended to be carried out by [[Charles Babbage]]'s [[Analytical Engine]].<ref name="IEEE">{{Cite journal | last1 = Fuegi | first1 = J. | last2 = Francis | first2 = J. | title = Lovelace & Babbage and the Creation of the 1843 'notes' | journal = IEEE Annals of the History of Computing | volume = 25 | issue = 4 | pages = 16 | year = 2003 | doi = 10.1109/MAHC.2003.1253887}}</ref> The algorithm, which was conveyed through notes on a translation of Luigi Federico Menabrea's paper on the analytical engine was mainly conceived by Lovelace as can be discerned through her correspondence with Babbage. However, Charles Babbage himself had written a program for the AE in 1837.<ref name="IEEE2021">{{Cite journal | last1 = Rojas | first1 = R. | title = The Computer Programs of Charles Babbage | journal = IEEE Annals of the History of Computing | volume = 43 | issue = 1 | pages = 6–18 | year = 2021 | doi = 10.1109/MAHC.2020.3045717}}</ref><ref name="IEEE2024">{{Cite journal | last1 = Rojas | first1 = R. | title = The First Computer Program | journal = Communications of the ACM | volume = 67 | issue = 6 | pages = 78–81 | year = 2024 | doi = 10.1145/3624731| doi-access = free | url = https://refubium.fu-berlin.de/bitstream/fub188/44090/1/3624731.pdf }}</ref> Lovelace was also the first to see a broader application for the analytical engine beyond mathematical calculations.  

In the 1880s, [[Herman Hollerith]] invented the concept of storing ''data'' in machine-readable form.<ref>{{cite web|url=http://www.columbia.edu/acis/history/hollerith.html|title=Columbia University Computing History – Herman Hollerith|last=da Cruz|first=Frank|date=2020-03-10|website=Columbia University|publisher=Columbia.edu|url-status=live|archive-url=https://web.archive.org/web/20200429210742/http://www.columbia.edu/cu/computinghistory/hollerith.html|archive-date=2020-04-29|access-date=2010-04-25}}</ref> Later a [[plugboard|control panel]] (plug board) added to his 1906 Type I Tabulator allowed it to be programmed for different jobs, and by the late 1940s, [[unit record equipment]] such as the [[IBM 602]] and [[IBM 604]], were programmed by control panels in a similar way, as were the first [[electronic computer]]s. However, with the concept of the [[stored-program computer]] introduced in 1949, both programs and data were stored and manipulated in the same way in [[computer memory]].<ref>{{cite web |title=Memory & Storage {{!}} Timeline of Computer History {{!}} Computer History Museum |url=https://www.computerhistory.org/timeline/memory-storage/ |website=www.computerhistory.org |access-date=3 June 2021 |archive-date=May 27, 2021 |archive-url=https://web.archive.org/web/20210527071533/https://www.computerhistory.org/timeline/memory-storage/ |url-status=live }}</ref>

[[Machine code]] was the language of early programs, written in the [[instruction set architecture|instruction set]] of the particular machine, often in [[binary numeral system|binary]] notation. [[Assembly language]]s were soon developed that let the programmer specify instructions in a text format (e.g., ADD X, TOTAL), with abbreviations for each operation code and meaningful names for specifying addresses. However, because an assembly language is little more than a different notation for a machine language,  two machines with [[Comparison of instruction set architectures|different instruction sets]] also have different assembly languages.

Using [[Test automation|automated tests]] and [[Fitness function|fitness functions]] can help to maintain some of the aforementioned attributes.<ref>{{Cite book |title=Fundamentals of Software Architecture: An Engineering Approach |publisher=O'Reilly Media |year=2020 |isbn=978-1492043454}}</ref>

[[File:First Computer Bug, 1945.jpg|thumb|The first known actual bug causing a problem in a computer was a moth, trapped inside a Harvard mainframe, recorded in a log book entry dated September 9, 1947.<ref>{{cite web| url = https://www.nationalgeographic.org/thisday/sep9/worlds-first-computer-bug| title = Photograph courtesy Naval Surface Warfare Center, Dahlgren, Virginia, from National Geographic Sept. 1947| date = July 15, 2020| access-date = November 10, 2020| archive-date = November 13, 2020| archive-url = https://web.archive.org/web/20201113163443/https://www.nationalgeographic.org/thisday/sep9/worlds-first-computer-bug/| url-status = live}}</ref> "Bug" was already a common term for a software defect when this insect was found.]]

Debugging is often done with [[Integrated development environment|IDE]]s. Standalone debuggers like [[GDB]] are also used, and these often provide less of a visual environment, usually using a [[command line]]. Some text editors such as [[Emacs]] allow GDB to be invoked through them, to provide a visual environment.

Many computer languages provide a mechanism to call functions provided by [[shared library|shared libraries]]. Provided the functions in a library follow the appropriate run-time conventions (e.g., method of passing [[argument (computer science)|arguments]]), then these functions may be written in any other language.

Learning to program has a long history related to professional standards and practices, academic initiatives and curriculum, and commercial books and materials for students, self-taught learners, hobbyists, and others who desire to create or customize software for personal use. Since the 1960s, learning to program has taken on the characteristics of a ''popular movement'', with the rise of academic disciplines, inspirational leaders, collective identities, and strategies to grow the movement and make institutionalize change.<ref>{{cite book |last1=Halvorson |first1=Michael J. |title=Code Nation: Personal Computing and the Learn to Program Movement in America |date=2020 |publisher=ACM Books |location=New York, NY |pages=3–6}}</ref> Through these social ideals and educational agendas, learning to code has become important not just for scientists and engineers, but for millions of citizens who have come to believe that creating software is beneficial to society and its members.

[[Computer magazine|Computer magazines]] and journals also provided learning content for professional and hobbyist programmers. A partial list of these resources includes ''[[Amiga World]]'', ''[[Byte (magazine)]]'', ''[[Communications of the ACM]]'', ''[[Computer (magazine)]]'', ''[[Compute!]]'', ''Computer Language (magazine)'', ''[[Computers and Electronics]]'', ''[[Dr. Dobb's Journal]]'', ''[[IEEE Software]]'', ''[[Macworld]]'', ''[[PC Magazine]]'', ''[[PC/Computing]]'', and ''[[UnixWorld]]''.

Important Internet resources for learning to code included blogs, wikis, videos, online databases, subscription sites, and custom websites focused on coding skills. New commercial resources included [[YouTube]] videos, Lynda.com tutorials (later [[LinkedIn Learning]]), [[Khan Academy]], [[Codecademy]], [[GitHub]], [[W3Schools]], [[Codewars]], and numerous [[Coding bootcamp|coding bootcamps]].

Most software development systems and [[game engine|game engines]] included rich online help resources, including [[integrated development environment|integrated development environments]] (IDEs), [[context-sensitive help]], [[API|APIs]], and other digital resources. Commercial [[software development kit|software development kits]] (SDKs) also provided a collection of software development tools and documentation in one installable package.

Commercial and non-profit organizations published learning websites for developers, created blogs, and established newsfeeds and social media resources about programming. Corporations like [[Apple Inc.|Apple]], [[Microsoft]], [[Oracle Corporation|Oracle]], [[Google]], and [[Amazon (company)|Amazon]] built corporate websites providing support for programmers, including resources like the [[Microsoft Developer Network]] (MSDN). Contemporary movements like Hour of Code ([[Code.org]]) show how learning to program has become associated with digital learning strategies, education agendas, and corporate philanthropy.

{{div col end}}Although programming has been presented in the media as a somewhat mathematical subject, some research shows that good programmers have strong skills in natural human languages, and that learning to code is similar to learning a [[foreign language]].<ref>{{Cite journal|last1=Prat|first1=Chantel S.|last2=Madhyastha|first2=Tara M.|last3=Mottarella|first3=Malayka J.|last4=Kuo|first4=Chu-Hsuan|date=2020-03-02|title=Relating Natural Language Aptitude to Individual Differences in Learning Programming Languages|journal=Scientific Reports|language=en|volume=10|issue=1|pages=3817|doi=10.1038/s41598-020-60661-8|pmid=32123206|issn=2045-2322|pmc=7051953|bibcode=2020NatSR..10.3817P}}</ref><ref>{{Cite web |date=2020-12-15 |title=To the brain, reading computer code is not the same as reading language |url=https://news.mit.edu/2020/brain-reading-computer-code-1215 |access-date=2023-07-29 |website=MIT News {{!}} Massachusetts Institute of Technology |language=en}}</ref>

*{{Cite journal|last=Smith|first=Erika E.|date=2013|title=Recognizing a Collective Inheritance through the History of Women in Computing|journal=CLCWeb: Comparative Literature & Culture |volume=15|issue=1|pages=1–9|doi=10.7771/1481-4374.1972 |doi-access=free}}