KOMPUTER PROGRAMING
Computer programming (often shortened to programming or coding) is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages.
The purpose of programming is to create a set of instructions that
computers use to perform specific operations or to exhibit desired
behaviors. The process of writing source code often requires expertise
in many different subjects, including knowledge of the application
domain, specialized algorithms and formal logic.
Overview
Within software engineering, programming (the implementation) is regarded as one phase in a software development process.
There is an ongoing debate on the extent to which the writing of programs is an art, a craft or an engineering 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,
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." 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 use of AdaCore
and security clearance). However, representing oneself as a
"Professional Software Engineer" without a license from an accredited
institution is illegal in many parts of the world.
Another ongoing debate is the extent to which the programming language used in writing computer programs affects the form that the final program takes. This debate is analogous to that surrounding the Sapir–Whorf hypothesis[2] in linguistics and cognitive science,
which postulates that a particular spoken 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.
History
See also: History of programming languages
The Antikythera mechanism from ancient Greece was a calculator utilizing gears of various sizes and configuration to determine its operation,[3] which tracked the metonic cycle still used in lunar-to-solar calendars, and which is consistent for calculating the dates of the Olympiads.[4] Al-Jazari built programmable Automata in 1206. One system employed in these devices was the use of pegs and cams placed into a wooden drum at specific locations. which would sequentially trigger levers that in turn operated percussion instruments. The output of this device was a small drummer playing various rhythms and drum patterns.[5][6] The Jacquard Loom, which Joseph Marie Jacquard developed in 1801, uses a series of pasteboard
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 adopted the use of punched cards around 1830 to control his Analytical Engine. The first computer program was written for the Analytical Engine by mathematician Ada Lovelace to calculate a sequence of Bernoulli Numbers.[7]
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.
In the late 1880s, Herman Hollerith
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..."[8] To process these punched cards, first known as "Hollerith cards" he invented the tabulator, and the keypunch machines. These three inventions were the foundation of the modern information processing industry. In 1896 he founded the Tabulating Machine Company (which later became the core of IBM). The addition of a control panel
(plugboard) 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 control panel programmable machines, called unit record equipment, to perform data-processing tasks.
The invention of the von Neumann architecture allowed computer programs to be stored in computer memory.
Early programs had to be painstakingly crafted using the instructions
(elementary operations) of the particular machine, often in binary notation. Every model of computer would likely use different instructions (machine language) 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).
Entering a program in assembly language is usually more convenient,
faster, and less prone to human error than using machine language, but
because an assembly language is little more than a different notation
for a machine language, any two machines with different instruction sets
also have different assembly languages.
In 1954, FORTRAN was invented; it was the first high level programming language to have a functional implementation, as opposed to just a design on paper.[9][10]
(A high-level language is, in very general terms, any programming
language that allows the programmer to write programs in terms that are
more abstract
than assembly language instructions, i.e. at a level of abstraction
"higher" than that of an assembly language.) 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,
which translates the FORTRAN program into machine language. In fact,
the name FORTRAN stands for "Formula Translation". 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 that 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. (Usually, an error in punching a
card meant that the card had to be discarded and a new one punched to
replace it.)
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
source code. However, high-level languages are still impractical for a
few programs, such as those where low-level hardware control is
necessary or where maximum processing speed is vital.
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.[citation needed]
Modern Programing