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History of C++

May 04 2008 at 11:02 pm, by ADMINISTRATOR

Computer languages have undergone dramatic evolution since the first electronic computers were built to assist in telemetry calculations during World War II. Early on, programmers worked with the most primitive computer instructions: machine language. These instructions were represented with strings of ones and zeroes. Assemblers were invented to map machine instructions to human-readable and -manageable mnemonics.

C++ evolved from C, which evolved from two programming languages BPCL and B. Martin Richards in 1967 developed BPCL for writing OS. Ken Thompson modeled many features of BPCL in his language B. The C Language was then evolved by Dennis Ritchie at Bell laboratories. C uses many concepts of BPCL and B. The widespread use of C with various types of computers unfortunately led to many variations. It became clear that a standard version of C was required. In 1983, the American National Standards created a committee to provide an unambiguous and independent definition of language which was then approved by 1989.This was called ANSI C. C++ an extension of C was developed by Bjarne Stroustoup in early 1980s at Bell Laboratories.

As object-oriented analysis, design, and programming began to catch on, Bjarne Stroustrup took the most popular language for commercial software development, C, and extended it to provide the features needed to facilitate object-oriented programming. He created C++, and in less than a decade it has gone from being used by only a handful of developers at AT&T to being the programming language of choice for an estimated one million developers worldwide. It is expected that by the end of the decade, C++ will be the predominant language for commercial software development.

While it is true that C++ is a superset of C, and that virtually any legal C program is a legal C++ program, the leap from C to C++ is very significant. C++ benefited from its relationship to C for many years, as C programmers could ease into their use of C++. To really get the full benefit of C++, however, many programmers found they had to unlearn much of what they knew and learn a whole new way of conceptualizing and solving programming problems. It provided number of features that spruce up the C language. It provided capabilities for object-oriented programming which is nicknamed as OOPS, is described in the next section.

"For many years, the principle goal of computer programmers was to write short pieces of code that would execute quickly. The program needed to be small, because memory was expensive, and it needed to be fast, because processing power was also expensive. As computers have become smaller, cheaper, and faster, and as the cost of memory has fallen, these priorities have changed. Today the cost of a programmer″s time far outweighs the cost of most of the computers in use by businesses. Well-written, easy-to-maintain code is at a premium. Easy- to-maintain means that as business requirements change, the program can be extended and enhanced without great expense."

Soon after the higher-level languages evolved, such as BASIC and COBOL. These languages let people work with something approximating words and sentences, such as Let I = 100. These instructions were translated back into machine language by interpreters and compilers. An interpreter translates a program as it reads it, turning the program instructions, or code, directly into actions. A compiler translates the code into an intermediary form. This step is called compiling, and produces an object file. The compiler then invokes a linker, which turns the object file into an executable program.

Compilers produce a program that is very fast each time it is run. However, the time-consuming task of translating the source code into machine language has already been accomplished. Another advantage of many compiled languages like C++ is that one can distribute the executable program to personels who don″t have the compiler. With an interpretive language, you must have the language to run the program.

Posted by ADMINISTRATOR | Views: 250 | Comments: 0 | User Group: Admin Group