<programming> A {function} provided by a {class} in {C++} and
	some other {object-oriented languages} to delete an object,
	the inverse of a {constructor}.

	(1998-04-28)

<object-oriented> In {object-oriented programming}, an
	instance of the data structure and behaviour defined by the
	object's {class}.  Each object has its own values for the
	{instance variables} of its class and can respond to the
	{methods} defined by its class.

	For example, an object of the "Point" class might have
	instance variables "x" and "y" and might respond to the "plot"
	method by drawing a dot on the screen at those coordinates.

	(2004-01-26)

1. Not simulated.  Often used as a specific antonym to
	{virtual} in any of its jargon senses.

	2. <mathematics> {real number}.

	[{Jargon File}]

	(1997-03-12)

1. <language, programming> {programming language}.

	2. <human language> {natural language}.

	(1998-09-07)

The consensus, idea, plan, story, or set of rules that is
	currently being used to inform a behaviour.  This usage is a
	generalisation and (deliberate) abuse of the technical
	meaning.  "What's the theory on fixing this TECO loss?"
	"What's the theory on dinner tonight?"  ("Chinatown, I
	guess.")  "What's the current theory on letting lusers on
	during the day?"  "The theory behind this change is to fix the
	following well-known screw...."

	(1994-12-14)

1. The art of debugging a blank sheet of paper (or, in these
	days of on-line editing, the art of debugging an empty file).

	2. A pastime similar to banging one's head against a wall, but
	with fewer opportunities for reward.

	3. The most fun you can have with your clothes on (although
	clothes are not mandatory).

	[{Jargon File}]

	(2003-02-12)

<programming> (OOD) A design method in which a system is
	modelled as a collection of cooperating {objects} and
	individual objects are treated as instances of a {class}
	within a {class hierarchy}.  Four stages can be identified:
	identify the classes and objects, identify their {semantics},
	identify their relationships and specify class and object
	interfaces and implementation.  Object-oriented design is one
	of the stages of {object-oriented programming}.

	["Object-oriented analysis and design with applications",
	Grady Booch, 2nd ed., pub. Benjamin/Cummings, Redwood CA,
	1994].

	(1997-12-07)

<language> One of the most used {object-oriented} languages, a
	superset of {C} developed primarily by {Bjarne Stroustrup}
	<bs@alice.att.com> at {AT&T} {Bell Laboratories} in 1986.

	In C++ a {class} is a user-defined {type}, syntactically a
	{struct} with {member functions}.  {Constructors} and
	{destructors} are member functions called to create or destroy
	{instances}.  A {friend} is a nonmember function that is
	allowed to access the private portion of a class.  C++ allows
	{implicit type conversion}, {function inlining}, {overloading}
	of operators and function names, and {default function
	arguments}.  It has {streams} for I/O and {references}.

	C++ 2.0 (May 1989) introduced {multiple inheritance},
	{type-safe linkage}, pointers to members, and {abstract
	classes}.

	C++ 2.1 was introduced in ["Annotated C++ Reference Manual",
	B. Stroustrup et al, A-W 1990].

	{MS-DOS
	(ftp://grape.ecs.clarkson.edu/pub/msdos/djgpp/djgpp.zip)},
	{Unix ANSI C++
	(ftp://gnu.org/pub/gnu/g++-1.39.0.tar.Z)} - X3J16
	committee. (They're workin' on it).

	See also {cfront}, {LEDA}, {uC++}.

	{Usenet} newsgroup: {news:comp.lang.c++}.

	["The C++ Programming Language", Bjarne Stroustrup, A-W,
	1986].

	(1996-06-06)

<jargon> /kluhj/ (From the old Scots "kludgie" meaning an
	outside toilet) A Scottish engineering term for anything added
	in an ad hoc (and possibly unhygenic!) manner.  At some point
	during the Second World War, Scottish engineers met Americans
	and the meaning, spelling and pronunciation of kludge became
	confused with that of "{kluge}".

	The spelling "kludge" was apparently popularised by the
	"Datamation" cited below which defined it as "An ill-assorted
	collection of poorly matching parts, forming a distressing
	whole."

	The result of this tangled history is a mess; in 1993, many
	(perhaps even most) hackers pronounce the word /klooj/ but
	spell it "kludge" (compare the pronunciation drift of {mung}).
	Some observers consider this appropriate in view of its
	meaning.

	["How to Design a Kludge", Jackson Granholme, Datamation,
	February 1962, pp. 30-31].

	[{Jargon File}]

	(1998-12-09)

<software> Instructions for a computer in some programming
	language, often {machine language}.  The word "code" is often
	used to distinguish instructions from {data} (e.g. "The code
	is marked 'read-only'") whereas "{software}" is used in
	contrast with "{hardware}" and may consist of more than just
	code.

	(2000-04-08)

<job> (Or "computer programmer", "developer") Someone who
	writes or debugs {computer programs}, for a living or for fun.
	"Analyst/developer" is a common equivalent job title, implying
	the added role of {system analysis}.  The term may be
	qualified according to the type of software - "{application}
	programmer", "{system programmer}", etc.

	(2000-01-24)

/de'moh/ 1. A demonstration of a product, often of an early
	version or prototype.  A demo is a far more effective way of
	inducing bugs to manifest themselves than any number of {test}
	runs, especially when important people are watching.

	2. {demo version}.

	3. A program written to demonstrate the programmer's coding
	ability and/or the power of the computer it runs on.  Such
	demos are nearly always written in {machine code} and
	traditionally feature scrolling text about the author, his
	friends, his code and anything else he fancies and animated
	graphics.

	[{Jargon File}]

	(1994-11-04)

1. {application program}.

	2. {function application}.

<World-Wide Web> The {World-Wide Web} {search engine} that
	indexes the greatest number of web pages - over two billion by
	December 2001 and provides a free service that searches this
	index in less than a second.

	The site's name is apparently derived from "{googol}", but
	note the difference in spelling.

	The "Google" spelling is also used in "The Hitchhikers Guide
	to the Galaxy" by Douglas Adams, in which one of Deep
	Thought's designers asks, "And are you not," said Fook,
	leaning anxiously foward, "a greater analyst than the
	Googleplex Star Thinker in the Seventh Galaxy of Light and
	Ingenuity which can calculate the trajectory of every single
	dust particle throughout a five-week Dangrabad Beta sand
	blizzard?"

	{Home (http://www.google.com/)}.

	(2001-12-28)

<body> A business, generally a large one.

	(1994-11-22)

<job> (Or "computer programmer", "developer") Someone who
	writes or debugs {computer programs}, for a living or for fun.
	"Analyst/developer" is a common equivalent job title, implying
	the added role of {system analysis}.  The term may be
	qualified according to the type of software - "{application}
	programmer", "{system programmer}", etc.

	(2000-01-24)

<programming> An individual {object} of a certain {class}.
	While a class is just the type definition, an actual usage of
	a class is called "instance".  Each instance of a class can
	have different values for its {instance variables}, i.e. its
	{state}.

	(1998-03-06)

1. <programming> An {address}, from the point of view of a
	programming language.  A pointer may be typed, with its {type}
	indicating the type of data to which it points.

	The terms "pointer" and "reference" are generally
	interchangable although particular programming languages often
	differentiate these two in subtle ways.  For example, {Perl}
	always calls them references, never pointers.  Conversely, in
	C, "pointer" is used, although "a reference" is often used to
	denote the concept that a pointer implements.

	{Anthony Hoare} once said:

	Pointers are like jumps, leading wildly from one part of the
	data structure to another.  Their introduction into high-level
	languages has been a step backward from which we may never
	recover.

	[C.A.R.Hoare "Hints on Programming Language Design", 1973,
	Prentice-Hall collection of essays and papers by Tony Hoare].

	2. <operating system> (Or "mouse pointer") An {icon}, usually
	a small arrow, that moves on the screen in response to
	movement of a {pointing device}, typically a {mouse}.  The
	pointer shows the user which object on the screen will be
	selected etc. when a mouse button is clicked.

	(1999-07-07)

1. <programming> An {address}, from the point of view of a
	programming language.  A pointer may be typed, with its {type}
	indicating the type of data to which it points.

	The terms "pointer" and "reference" are generally
	interchangable although particular programming languages often
	differentiate these two in subtle ways.  For example, {Perl}
	always calls them references, never pointers.  Conversely, in
	C, "pointer" is used, although "a reference" is often used to
	denote the concept that a pointer implements.

	{Anthony Hoare} once said:

	Pointers are like jumps, leading wildly from one part of the
	data structure to another.  Their introduction into high-level
	languages has been a step backward from which we may never
	recover.

	[C.A.R.Hoare "Hints on Programming Language Design", 1973,
	Prentice-Hall collection of essays and papers by Tony Hoare].

	2. <operating system> (Or "mouse pointer") An {icon}, usually
	a small arrow, that moves on the screen in response to
	movement of a {pointing device}, typically a {mouse}.  The
	pointer shows the user which object on the screen will be
	selected etc. when a mouse button is clicked.

	(1999-07-07)

<jargon> Different systems (e.g., {programs}, {file formats},
	{protocols}, even {programming languages}) that can work
	together or exchange data are said to be compatible.

	See also {backward compatible}, {forward compatible}.

	(1998-01-15)

<programming> A symbol used as a {function}, with {infix
	syntax} if it has two arguments (e.g. "+") or {prefix syntax} if
	it has only one (e.g. {Boolean} NOT).  Many languages use
	operators for built-in functions such as arithmetic and logic.

	(1995-04-30)

1. The {supervisor} program or {operating system} on a
	computer.

	2. The entire computer system, including input/output devices,
	the {supervisor} program or {operating system} and possibly
	other {software}.

	3. Any large program.

	4. Any method or {algorithm}.

	[{Jargon File}]

1. <programming> A collection of identically typed data items
	distinguished by their indices (or "subscripts").  The number
	of dimensions an array can have depends on the language but is
	usually unlimited.

	An array is a kind of {aggregate} data type.  A single
	ordinary variable (a "{scalar}") could be considered as a
	zero-dimensional array.  A one-dimensional array is also known
	as a "{vector}".

	A reference to an array element is written something like
	A[i,j,k] where A is the array name and i, j and k are the
	indices.  The {C} language is peculiar in that each index is
	written in separate brackets, e.g. A[i][j][k].  This expresses
	the fact that, in C, an N-dimensional array is actually a
	vector, each of whose elements is an N-1 dimensional array.

	Elements of an array are usually stored contiguously.
	Languages differ as to whether the leftmost or rightmost index
	varies most rapidly, i.e. whether each row is stored
	contiguously or each column (for a 2D array).

	Arrays are appropriate for storing data which must be accessed
	in an unpredictable order, in contrast to {lists} which are
	best when accessed sequentially.

	See also {associative array}.

	2. <architecture> A {processor array}, not to be confused with
	an {array processor}.

	(1995-01-25)

<networking> Name Daemon.

	<networking> A {Unix} {background} process that converts
	{hostnames} to {Internet addresses} for the {TCP/IP}
	{protocol}.

	{Unix manual page}: named(8).

	See also {DNS}.

	(1995-03-28)

<programming, operating system> A {variable} that is bound in
	the current environment.  When evaluating an expression in
	some environment, the evaluation of a variable consists of
	looking up its name in the environment and substituting its
	value.

	Most programming languages have some concept of an environment
	but in {Unix} {shell scripts} it has a specific meaning
	slightly different from other contexts.  In shell scripts,
	environment variables are one kind of {shell variable}.  They
	differ from {local variables} and {command line arguments} in
	that they are inheritted by a {child process}.  Examples are
	the PATH variable that tells the shell the {file system}
	{paths} to search to find command {executables} and the TZ
	variable which contains the local time zone.  The variable
	called "SHELL" specifies the type of shell being used.

	These variables are used by commands or {shell scripts} to
	discover things about the environment they are operating in.
	Environment variables can be changed or created by the {user}
	or a program.

	To see a list of environment variables type "setenv" at the
	{csh} or {tcsh} {prompt} or "set" at the {sh}, {bash}, {jsh}
	or {ksh} prompt.

	In other programming languages, e.g. {functional programming}
	languages, the environment is extended with new bindings when
	a {function}'s {parameters} are bound to its {actual
	arguments} or when new variables are declared.  In a
	{block-structured} {procedural} language, the environment
	usually consists of a {linked list} of {activation records}.

	(1999-01-26)

1. <mathematics> A {set} containing a certain number of
	objects selected from another set.

	The number of combinations of r objects chosen from a set of n
	is

		n C r = n! / ((n-r)! r!)

	where "n C r" is normally with n and r as subscripts or as n
	above r in parentheses.

	See also {permutation}.

	2. <reduction> In the theory of {combinators}, a combination
	denotes an expression in which {function application} is the
	only operation.

	(1995-04-10)

1. (Or "finite", "isolated") In {domain theory}, an element d
	of a {cpo} D is compact if and only if, for any {chain} S, a
	subset of D,

		d <= lub S  =>  there exists s in S such that d <= s.

	I.e. you always reach d (or better) after a finite number of
	steps up the chain.

	("<=" is written in {LaTeX} as {\sqsubseteq}).

	[{Jargon File}]

	(1995-01-13)

	2. Of a design, describes the valuable property that it can
	all be apprehended at once in one's head.  This generally
	means the thing created from the design can be used with
	greater facility and fewer errors than an equivalent tool that
	is not compact.  Compactness does not imply triviality or lack
	of power; for example, {C} is compact and {Fortran} is not,
	but C is more powerful than Fortran.  Designs become
	non-compact through accreting {features} and {cruft} that
	don't merge cleanly into the overall design scheme (thus, some
	fans of {Classic C} maintain that {ANSI C} is no longer
	compact).

	(1995-01-13)

<system> The degree to which a system suffers degradation or
	interruption in its service to the customer as a consequence
	of failures of one or more of its parts.

	One of the components of {RAS}.

	(2000-08-13)

<programming> (Or "computer program", "program", "code") The
	instructions executed by a computer, as opposed to the
	physical device on which they run (the "{hardware}").

	The term was coined by the eminent statistician, {John Tukey}.

	Programs stored on {non-volatile storage} built from
	{integrated circuits} (e.g. {ROM} or {PROM}) are usually
	called {firmware}.

	Software can be split into two main types - {system software}
	and application software or {application programs}.  System
	software is any software required to support the production or
	execution of application programs but which is not specific to
	any particular application.  Examples of system software would
	include the {operating system}, {compilers}, editors and
	sorting programs.

	Examples of application programs would include an accounts
	package or a {CAD} program.  Other broad classes of
	application software include {real-time} software, {business
	software}, scientific and engineering software, {embedded
	software}, personal computer software and {artificial
	intelligence} software.

	Software includes both {source code} written by humans and
	executable {machine code} produced by {assemblers} or
	{compilers}.  It does not usually include the data processed
	by programs unless this is in a format such as {multimedia}
	which depends on the use of computers for its presentation.
	This distinction becomes unclear in cases such as {spread
	sheets} which can contain both instructions (formulae and
	{macros}) and data.  There are also various intermediate
	compiled or {semi-compiled}, forms of software such as
	{library} files and {byte-code}.

	Some claim that {documentation} (both paper and electronic) is
	also software.  Others go further and define software to be
	programs plus documentation though this does not correspond
	with common usage.

	The noun "program" describes a single, complete and
	more-or-less self-contained list of instructions, often stored
	in a single {file}, whereas "code" and "software" are
	uncountable nouns describing some number of instructions which
	may constitute one or more programs or part thereof.  Most
	programs, however, rely heavily on various kinds of {operating
	system} software for their execution.  The nounds "code" and
	"software" both refer to the same thing but "code" tends to
	suggest an interest in the implementation details whereas
	"software" is more of a user's term.

	(2002-07-21)