C++ evolved from C which evolved from two previous language,
BCPL and B. BCPL was developed in 1967 by martin Richards as a language for
writing operating systems software and compilers. Ken Thompson modeled many
features in his language be after their counterparts in BCPL and used b to
create early versions of the unix operating system at bell laboratories in 1970
on a digital Equipment corporation PDP-7 computer Both BCPL and be were"typless"
language- every data item occupied one"word" in memory. For example
it was the programmer's responsibility to treat a data item as a whole number
or a real number.
The C language was
evolved from b by Dennis Ritchie at bell
laboratories and was originally Implemented on a DEC PDP-11 computer in 1972. C
uses many important concepts of
BCPL and B while adding data typing and other features. C initially became widely
known as the development language of the Unix operating system. Today,
virtually all new major operating systems are written in C and/orC++. Over the
past two decades, c has become available for most computers. C is hardware
independent. With careful design, it is possible to write C programs that are
portable to most computers.
By the late 1970s, C had evolved into what is now referred to
as " traditional C," or " kernighan and ritchie C," The
publication by prentice hall in 1978 of kernighn and Ritchie's book, The C
programming language, brought wide attention to the language. This publication
became one of the most successful
computer science books ever. The widespread use of C with various types of
computers[ sometimes called hardware platforms] led to many variations. These
were similar, but often incompatible.
This was a serious problem for programmers who needed to write portable programs that would run on
several platforms.. It became clear that a standard version of C was needed. in
1983, the X3j11 technical committee was created under the American national
standards committee on computers and information processing[X3] to "provide
an unambiguous and machine- independent definition of the language." In
1989, the standard was approved. Ansi cooperated with the international standard
organization[ISO] to standardize C
worldwide; the joint standard document was published in 1990 and is referred to
as ANSI/ISO 9899: 1990. The second edition of kernighan and ritchie, published
in 1988, reflects this version called ANSI C, a version of the language now
used worldwide[Ke88].
C++, an extension of C, was developed by bjarne stroustrup
in the early 1980s at bell laboratories. C++ provides a number of features
that"spruce up" the C language, but more important, it provides
capabilities for object- oriented programming. C++ was recently standardized by
the ANSI and ISO committiees.
There is a revolution brewing in the software community.
Building software Quickly, correctly and economically remains and clusive
goal, and this at a time when demands
for new and more powerful software are soaring. Objects are essentially
reusable software components that model
items in the real world. software
developers are discovering that using a modular, object- oriented design and
Implementation approach can make software development groups much more
productive than is possible with previous popular programming Techniques such
as structured programming. Object- oriented programs are often easier to
understand, correct and modify.
Many
other object- oriented languages have been developed, including smalltalk,
developed at Xerox's palo alto research center[PARC].Smalltalk is a pure
object- oriented language_ literally everything is an object.C++ is a hybrid
language_ it is possible to program in either a C_ like style, an object_
oriented style or both.
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