Computer programming (often shortened to programming or coding) is the process of writing, testing, debugging Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware, thus making it behave as expected. Debugging tends to be harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge in another. Many entire books have been written/troubleshooting Troubleshooting is a form of problem solving, often applied to repair failed products or processes. It is a logical, systematic search for the source of a problem so that it can be solved, and so the product or process can be made operational again. Troubleshooting is needed to develop and maintain complex systems where the symptoms of a problem, and maintaining the source code In computer science, source code is any collection of statements or declarations written in some human-readable computer programming language. Source code is the means most often used by programmers to specify the actions to be performed by a computer of computer programs A computer program is a sequence of instructions written to perform a specified task for a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute the instructions. The same program in its human-. This source code is written in a programming language A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine, to express algorithms precisely, or as a mode of human communication. The code may be a modification of an existing source or something completely new. The purpose of programming is to create a program that exhibits a certain desired behaviour (customization). The process of writing source code often requires expertise in many different subjects, including knowledge of the application domain, specialized algorithms In mathematics, computer science, and related subjects, an 'algorithm' is an effective method for solving a problem expressed as a finite sequence of instructions. Algorithms are used for calculation, data processing, and many other fields and formal logic Logic is the study of reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, and computer science. Logic examines general forms which arguments may take, which forms are valid, and which are fallacies. It is one kind of critical thinking. In philosophy, the study of logic.

Overview

Within software engineering Software engineering is a profession and field of study dedicated to designing, implementing, and modifying software so that it is of higher quality, more affordable, maintainable, and faster to build. The term software engineering first appeared in the 1968 NATO Software Engineering Conference, and was meant to provoke thought regarding the, programming (the implementation) is regarded as one phase in a software development process A software development process is a structure imposed on the development of a software product. Similar terms include software life cycle and software process. There are several models for such processes, each describing approaches to a variety of tasks or activities that take place during the process. Some people consider a lifecycle model a more.

There is an ongoing debate on the extent to which the writing of programs is an art Art is the process or product of deliberately arranging elements in a way to affect the senses or emotions. It encompasses a diverse range of human activities, creations, and modes of expression, including music, literature, film, photography, sculpture, and paintings. The meaning of art is explored in a branch of philosophy known as aesthetics, a craft A craft is a skill, especially involving practical arts. It may refer to a trade or particular art or an engineering Engineering is the discipline, art and profession of acquiring and applying technical, scientific, and mathematical knowledge to design and implement materials, structures, machines, devices, systems, and processes that safely realize a desired objective or invention discipline.^[1] In general, good programming is considered to be the measured application of all three, with the goal of producing an efficient and evolvable software solution (the criteria for "efficient" and "evolvable" vary considerably). The discipline differs from many other technical professions in that programmers A programmer, computer programmer or coder is someone who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst. A, in general, do not need to be licensed or pass any standardized (or governmentally regulated) certification tests in order to call themselves "programmers" or even "software engineers." However, representing oneself as a "Professional Software Engineer" Professional Engineer is the term for registered or licensed engineers in some countries who are permitted to offer their professional services directly to the public without a license from an accredited institution is illegal in many parts of the world.^{[citation needed]} However, because the discipline covers many areas, which may or may not include critical applications, it is debatable whether licensing is required for the profession as a whole. In most cases, the discipline is self-governed by the entities which require the programming, and sometimes very strict environments are defined (e.g. United States Air Force The United States Air Force is the aerial warfare, space warfare, and cyberwarfare branch of the U.S. armed forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947. It is the most recent branch use of AdaCore AdaCore is a computer software company that develops development tools for the Ada programming language, including compilers, tools and libraries. Its main product is GNAT Pro, a compiler that supports all Ada versions and security clearance).

Another ongoing debate is the extent to which the programming language A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine, to express algorithms precisely, or as a mode of human communication used in writing computer programs A computer program is a sequence of instructions written to perform a specified task for a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute the instructions. The same program in its human- affects the form that the final program takes. This debate is analogous to that surrounding the Sapir-Whorf hypothesis The linguistic relativity principle is the idea that the varying cultural concepts and categories inherent in different languages affect the cognitive classification of the experienced world in such a way that speakers of different languages think and behave differently because of it. Roger Brown has drawn a distinction between weak linguistic ^[2] in linguistics Linguistics is the scientific study of natural language. Linguistics encompasses a number of sub-fields. An important topical division is between the study of language structure and the study of meaning (semantics and pragmatics). Grammar encompasses morphology (the formation and composition of words), syntax (the rules that determine how words, that postulates that a particular language's nature influences the habitual thought of its speakers. Different language patterns yield different patterns of thought. This idea challenges the possibility of representing the world perfectly with language, because it acknowledges that the mechanisms of any language condition the thoughts of its speaker community.

Said another way, programming is the craft of transforming requirements In engineering, a requirement is a singular documented need of what a particular product or service should be or perform. It is most commonly used in a formal sense in systems engineering or software engineering. It is a statement that identifies a necessary attribute, capability, characteristic, or quality of a system in order for it to have into something that a computer A computer is a programmable machine that receives input, stores and manipulates data//information, and provides output in a useful format can execute.

History of programming

The concept of devices that operate following a pre-defined set of instructions traces back to Greek Mythology Greek mythology is the body of myths and legends belonging to the ancient Greeks concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece. Modern scholars refer to the myths and study them in an attempt to throw light on the, notably Hephaestus |} Hephaestus was a Greek god whose Roman equivalent was Vulcan. He is the son of Zeus and Hera (the King and Queen of the Gods). He was the god of technology, blacksmiths, craftsmen, artisans, sculptors, metals, metallurgy, fire and volcanoes. Like other mythic smiths but unlike most other gods, Hephaestus was lame, which gave him a grotesque and his mechanical slaves.^[3] The Antikythera mechanism The Antikythera mechanism , is conjectured to be an ancient mechanical computer designed to calculate astronomical positions. It was recovered in 1900–01 from the Antikythera wreck, but its complexity and significance were not understood until decades later. It is now thought to have been built about 150–100 BC. Technological artifacts of was a calculator utilizing gears of various sizes and configuration to determine its operation. Al-Jazari Abū al-'Iz Ibn Ismā'īl ibn al-Razāz al-Jazarī (Arabic: أَبُو اَلْعِزِ بْنُ إسْماعِيلِ بْنُ الرِّزاز الجزري‎) was a prominent Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, mathematician and astronomer from Al-Jazira, Mesopotamia, who lived during the Islamic Golden built programmable Automata A humanoid robot is a robot with its overall appearance, based on that of the human body, allowing interaction with made-for-human tools or environments. In general humanoid robots have a torso with a head, two arms and two legs, although some forms of humanoid robots may model only part of the body, for example, from the waist up. Some humanoid in 1206. One system employed in these devices was the use of pegs and cams A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path. The cam can be a simple tooth, as is used to deliver placed into a wooden drum at specific locations. which would sequentially trigger levers In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to multiply the mechanical force (effort) that can be applied to another object (load). This leverage is also termed mechanical advantage, and is one example of the principle of moments. A lever is one of the six simple machines that in turn operated percussion instruments A percussion instrument is any object which produces a sound when hit with an implement, shaken, rubbed, scraped, or by any other action which sets the object into vibration. The term usually applies to an object used in a rhythmic context or with musical intent. The output of this device was a small drummer playing various rhythms and drum patterns.^[4][5] The Jacquard Loom The Jacquard loom is a mechanical loom, invented by Joseph Marie Jacquard in 1801, that simplifies the process of manufacturing textiles with complex patterns such as brocade, damask, and matelasse. The loom is controlled by punchcards with punched holes, each row of which corresponds to one row of the design. Multiple rows of holes are punched on, which Joseph Marie Jacquard developed in 1801, uses a series of pasteboard Card stock, also called cover stock or pasteboard, is a paper stock that is thicker and more durable than normal writing or printing paper, but thinner and more flexible than other forms of paperboard. Card stock is often used for postcards, playing cards, catalog covers, scrapbooking, and other uses which require higher durability than regular cards with holes punched in them. The hole pattern represented the pattern that the loom had to follow in weaving cloth. The loom could produce entirely different weaves using different sets of cards. Charles Babbage Charles Babbage, FRS was an English mathematician, philosopher, inventor, and mechanical engineer who originated the concept of a programmable computer. Parts of his uncompleted mechanisms are on display in the London Science Museum. In 1991, a perfectly functioning difference engine was constructed from Babbage's original plans. Built to adopted the use of punched cards A punched card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions. Now almost an obsolete recording medium, punched cards were widely used throughout the 19th century for controlling textile looms and in the late 19th and early 20th century for operating fairground around 1830 to control his Analytical Engine The analytical engine, an important step in the history of computers, was the design of a mechanical general-purpose computer by English mathematician Charles Babbage. In its logical design the machine was essentially modern, anticipating the first completed general-purpose computers by about 100 years. It was first described in 1837. Babbage. The synthesis of numerical calculation, predetermined operation and output, along with a way to organize and input instructions in a manner relatively easy for humans to conceive and produce, led to the modern development of computer programming. Development of computer programming accelerated through the Industrial Revolution The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, and transport had a profound effect on the socioeconomic and cultural conditions starting in the United Kingdom, then subsequently spreading throughout Europe, North America, and eventually the world. The onset of the.

In the late 1880s, Herman Hollerith Herman Hollerith was a German-American statistician who developed a mechanical tabulator based on punched cards to rapidly tabulate statistics from millions of pieces of data. He was the founder of the company that became IBM invented the recording of data on a medium that could then be read by a machine. Prior uses of machine readable media, above, had been for control, not data. "After some initial trials with paper tape, he settled on punched cards A punched card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions. Now almost an obsolete recording medium, punched cards were widely used throughout the 19th century for controlling textile looms and in the late 19th and early 20th century for operating fairground..."^[6] To process these punched cards, first known as "Hollerith cards" he invented the tabulator The tabulating machine was an electrical device designed to assist in summarizing information and, later, accounting. Invented by Herman Hollerith, the machine was developed to help process data for the 1890 U.S. Census. It spawned a larger class of devices known as unit record equipment and the data processing industry, and the keypunch A keypunch is a device for manually entering data into punched cards by precisely punching holes at locations designated by the keys struck by the operator. Early keypunches were manual devices. Later keypunches were mechanized, often resembled a small desk, with a keyboard similar to a typewriter, and with hoppers for blank cards and stackers for machines. These three inventions were the foundation of the modern information processing industry. In 1896 he founded the Tabulating Machine Company Herman Hollerith was a German-American statistician who developed a mechanical tabulator based on punched cards to rapidly tabulate statistics from millions of pieces of data. He was the founder of the company that became IBM (which later became the core of IBM International Business Machines (NYSE: IBM) is a multinational computer, technology and IT consulting corporation headquartered in Armonk, North Castle, New York, United States. IBM is the world's fourth largest technology company and the second most valuable by global brand (after Coca-Cola). IBM is one of the few information technology companies). The addition of a control panel The term control panel was used for the plugboards in unit record equipment and early computers. Although debatable, the metaphor's popularity is attributed not to the Xerox Star or the Apple Lisa which pioneered the first graphical user interface metaphors. The operation of these machines did in fact appropriate windowed methods of controlled to his 1906 Type I Tabulator allowed it to do different jobs without having to be physically rebuilt. By the late 1940s, there were a variety of plug-board programmable machines, called unit record equipment Before the advent of electronic computers, data processing was performed using electromechanical devices called unit record equipment, electric accounting machines or tabulating machines. Unit record machines were as ubiquitous in industry and government in the first half of the twentieth century as computers became in the second half. They, to perform data-processing tasks (card reading). Early computer programmers used plug-boards for the variety of complex calculations requested of the newly invented machines.

The invention of the Von Neumann architecture The von Neumann architecture is a design model for a stored-program digital computer that uses a central processing unit and a single separate storage structure ("memory") to hold both instructions and data. It is named after the mathematician and early computer scientist John von Neumann. Such computers implement a universal Turing allowed computer programs to be stored in computer memory Computer memory refers to devices that are used to store data or programs on a temporary or permanent basis for use in an electronic digital computer. Computers represent information in binary code, written as sequences of 0s and 1s. Each binary digit (or "bit") may be stored by any physical system that can be in either of two stable. Early programs had to be painstakingly crafted using the instructions of the particular machine, often in binary The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2. Owing to its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used internally by all modern computers notation. Every model of computer would be likely to need different instructions to do the same task. Later assembly languages were developed that let the programmer specify each instruction in a text format, entering abbreviations for each operation code instead of a number and specifying addresses in symbolic form (e.g., ADD X, TOTAL). In 1954 Fortran was invented, being the first high level programming language to have a functional implementation.^[7][8] It allowed programmers to specify calculations by entering a formula directly (e.g. Y = X*2 + 5*X + 9). The program text, or source, is converted into machine instructions using a special program called a compiler. Many other languages were developed, including some for commercial programming, such as COBOL. Programs were mostly still entered using punched cards or paper tape. (See computer programming in the punch card era). By the late 1960s, data storage devices and computer terminals became inexpensive enough so programs could be created by typing directly into the computers. Text editors were developed that allowed changes and corrections to be made much more easily than with punched cards.

As time has progressed, computers have made giant leaps in the area of processing power. This has brought about newer programming languages that are more abstracted from the underlying hardware. Although these high-level languages usually incur greater overhead, the increase in speed of modern computers has made the use of these languages much more practical than in the past. These increasingly abstracted languages typically are easier to learn and allow the programmer to develop applications much more efficiently and with less code. However, high-level languages are still impractical for a few programs, such as those where low-level hardware control is necessary or where processing speed is at a premium.

Throughout the second half of the twentieth century, programming was an attractive career in most developed countries. Some forms of programming have been increasingly subject to offshore outsourcing (importing software and services from other countries, usually at a lower wage), making programming career decisions in developed countries more complicated, while increasing economic opportunities in less developed areas. It is unclear how far this trend will continue and how deeply it will impact programmer wages and opportunities.

Modern programming

Quality requirements

Whatever the approach to software development may be, the final program must satisfy some fundamental properties. The following properties are among the most relevant:

• Efficiency/performance: the amount of system resources a program consumes (processor time, memory space, slow devices such as disks, network bandwidth and to some extent even user interaction): the less, the better. This also includes correct disposal of some resources, such as cleaning up temporary files and lack of memory leaks.
• Reliability: how often the results of a program are correct. This depends on conceptual correctness of algorithms, and minimization of programming mistakes, such as mistakes in resource management (e.g., buffer overflows and race conditions) and logic errors (such as division by zero).
• Robustness: how well a program anticipates problems not due to programmer error. This includes situations such as incorrect, inappropriate or corrupt data, unavailability of needed resources such as memory, operating system services and network connections, and user error.
• Usability: the ergonomics of a program: the ease with which a person can use the program for its intended purpose, or in some cases even unanticipated purposes. Such issues can make or break its success even regardless of other issues. This involves a wide range of textual, graphical and sometimes hardware elements that improve the clarity, intuitiveness, cohesiveness and completeness of a program's user interface.
• Portability: the range of computer hardware and operating system platforms on which the source code of a program can be compiled/interpreted and run. This depends on differences in the programming facilities provided by the different platforms, including hardware and operating system resources, expected behaviour of the hardware and operating system, and availability of platform specific compilers (and sometimes libraries) for the language of the source code.
• Maintainability: the ease with which a program can be modified by its present or future developers in order to make improvements or customizations, fix bugs and security holes, or adapt it to new environments. Good practices during initial development make the difference in this regard. This quality may not be directly apparent to the end user but it can significantly affect the fate of a program over the long term.

Algorithmic complexity

The academic field and the engineering practice of computer programming are both largely concerned with discovering and implementing the most efficient algorithms for a given class of problem. For this purpose, algorithms are classified into orders using so-called Big O notation, O(n), which expresses resource use, such as execution time or memory consumption, in terms of the size of an input. Expert programmers are familiar with a variety of well-established algorithms and their respective complexities and use this knowledge to choose algorithms that are best suited to the circumstances.

Methodologies

The first step in most formal software development projects is requirements analysis, followed by testing to determine value modeling, implementation, and failure elimination (debugging). There exist a lot of differing approaches for each of those tasks. One approach popular for requirements analysis is Use Case analysis.

Popular modeling techniques include Object-Oriented Analysis and Design (OOAD) and Model-Driven Architecture (MDA). The Unified Modeling Language (UML) is a notation used for both the OOAD and MDA.

A similar technique used for database design is Entity-Relationship Modeling (ER Modeling).

Implementation techniques include imperative languages (object-oriented or procedural), functional languages, and logic languages.

Measuring language usage

It is very difficult to determine what are the most popular of modern programming languages. Some languages are very popular for particular kinds of applications (e.g., COBOL is still strong in the corporate data center, often on large mainframes, FORTRAN in engineering applications, scripting languages in web development, and C in embedded applications), while some languages are regularly used to write many different kinds of applications.

Methods of measuring programming language popularity include: counting the number of job advertisements that mention the language,^[9] the number of books teaching the language that are sold (this overestimates the importance of newer languages), and estimates of the number of existing lines of code written in the language (this underestimates the number of users of business languages such as COBOL).

Debugging

Debugging is a very important task in the software development process, because an incorrect program can have significant consequences for its users. Some languages are more prone to some kinds of faults because their specification does not require compilers to perform as much checking as other languages. Use of a static analysis tool can help detect some possible problems.

Debugging is often done with IDEs like Visual Studio, NetBeans, and Eclipse. Standalone debuggers like gdb are also used, and these often provide less of a visual environment, usually using a command line.

Programming languages

Different programming languages support different styles of programming (called programming paradigms). The choice of language used is subject to many considerations, such as company policy, suitability to task, availability of third-party packages, or individual preference. Ideally, the programming language best suited for the task at hand will be selected. Trade-offs from this ideal involve finding enough programmers who know the language to build a team, the availability of compilers for that language, and the efficiency with which programs written in a given language execute.

Allen Downey, in his book How To Think Like A Computer Scientist, writes:

The details look different in different languages, but a few basic instructions appear in just about every language:

• input: Get data from the keyboard, a file, or some other device.
• output: Display data on the screen or send data to a file or other device.
• arithmetic: Perform basic arithmetical operations like addition and multiplication.
• conditional execution: Check for certain conditions and execute the appropriate sequence of statements.
• repetition: Perform some action repeatedly, usually with some variation.

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

Programmers

Computer programmers are those who write computer software. Their jobs usually involve:

• Coding
• Compilation
• Documentation
• Integration
• Maintenance
• Requirements analysis
• Software architecture
• Software testing
• Specification
• Debugging

See also

• ACCU (organisation)
• Association for Computing Machinery
• Computer programming in the punch card era
• Hello world program
• List of basic computer programming topics
• List of computer programming topics
• Programming paradigms
• Software engineering
• The Art of Computer Programming

References

1. ^ Paul Graham (2003). Hackers and Painters. http://www.paulgraham.com/hp.html. Retrieved 2006-08-22.
2. ^ Kenneth E. Iverson, the originator of the APL programming language, believed that the Sapir–Whorf hypothesis applied to computer languages (without actually mentioning the hypothesis by name). His Turing award lecture, "Notation as a tool of thought", was devoted to this theme, arguing that more powerful notations aided thinking about computer algorithms. Iverson K.E.,"Notation as a tool of thought", Communications of the ACM, 23: 444-465 (August 1980).
3. ^ New World Encyclopedia Online Edition New World Encyclopedia
4. ^ A 13th Century Programmable Robot, University of Sheffield
5. ^ Fowler, Charles B. (October 1967), "The Museum of Music: A History of Mechanical Instruments", Music Educators Journal 54 (2): 45–49, doi:10.2307/3391092
6. ^ "Columbia University Computing History - Herman Hollerith". Columbia.edu. http://www.columbia.edu/acis/history/hollerith.html. Retrieved 2010-04-25.
7. ^ 12:10 p.m. ET (2007-03-20). "Fortran creator John Backus dies - Tech and gadgets- msnbc.com". MSNBC. http://www.msnbc.msn.com/id/17704662/. Retrieved 2010-04-25.
8. ^ "CSC-302 99S : Class 02: A Brief History of Programming Languages". Math.grin.edu. http://www.math.grin.edu/~rebelsky/Courses/CS302/99S/Outlines/outline.02.html. Retrieved 2010-04-25.
9. ^ Survey of Job advertisements mentioning a given language>

Further reading

• Weinberg, Gerald M., The Psychology of Computer Programming, New York: Van Nostrand Reinhold, 1971

External links

• Programming Wikia
• How to Think Like a Computer Scientist - by Jeffrey Elkner, Allen B. Downey and Chris Meyers

Categories: Software development process | Computer programming

See Also:

What Links Here:

Recently Viewed Pages:

• Domain Name Registrar: Encyclopedia
• Home
• Authoritative Name Server: Blogs
• .org: Encyclopedia
• .com: Encyclopedia
• Domain Name Reseller: News
• Web Site: Encyclopedia
• Uniform Resource Locator: Encyclopedia
• Top-level Domain: Encyclopedia
• DomainKeys: Encyclopedia

Most Popular Pages:

• Domain Name Registrar: Encyclopedia
• Baina
• Batua: Blogs
• Referrers
• Localhost: Blogs
• Vmware
• Content
• Computer Programming: Web Search
• Duen: Blogs
• Ipuin

Related 'Computer Programming' Searches: