C++ Ships Commercially — Bjarne Stroustrup

C++ is the programming language Bjarne Stroustrup designed at AT&T Bell Labs. Work began in 1979, under the name C with Classes. It was named C++ in 1983, and in October 1985 the first commercial implementation was released at the same time as Stroustrup's book The C++ Programming Language. The first ISO standard was C++98, in 1998.

That gives three answers to "when was C++ created?" This article follows what happened between them, drawing on Stroustrup's own A History of C++: 1979-1991, written for ACM's HOPL-II conference in 1993, and the FAQ on his website.

Prehistory: Simula and BCPL at Cambridge

The criteria that shaped C++ took form while Stroustrup was a PhD student at the University of Cambridge. To study how system software for a distributed system might be organised, he wrote a large simulator — first in Simula, on the university's IBM 360/165.

Simula's classes let him map the concepts of his application directly onto the language, and its type checking caught conceptual flaws in the design as well as slips. He was surprised to find the language helping more as the program grew. The implementation, however, did not scale. Separate compilation and linking were painfully slow, run-time performance was hopeless, and measurements showed more than 80% of the time going to the garbage collector — even though the simulated system never produced any garbage.

To save the project he rewrote the simulator in BCPL, which, he says, "makes C look like a very high level language" and offered no type checking or run-time support. It was horrible to write and debug, but it ran fast and gave him his results. Leaving Cambridge, he swore never again to attack a problem with tools that unsuitable.

What he wanted from a good tool came down to three things.

1979: C with Classes

By Stroustrup's account, the work that became C++ started in April 1979 at the Computing Science Research Center of Bell Labs in Murray Hill, New Jersey. The project was to analyse how far the UNIX kernel could be distributed over computers on a local network, which needed a way to express the module structure of a complex system and the communication between its modules — exactly the kind of problem he had vowed not to attack without proper tools.

By October 1979 he had Cpre running, a preprocessor that added Simula-like classes to C; the language it accepted was C with Classes. By March 1980 it supported one real project and several experiments and was in use on 16 systems. One decision proved crucial. Although concurrency was a primary aim, the language had no concurrency primitives; instead, inheritance and class member functions made it possible to write concurrency as a library, because there was no single dominant model of concurrency. That choice is what made C with Classes a general-purpose language rather than a C variant for a particular application area.

1982–83: Cfront and the name

In 1982 Stroustrup judged C with Classes a "medium success": useful enough to pay for itself and its developer, but not attractive enough to pay for a support organisation. He saw two ways out — stop supporting it, or build a better language with enough users to fund one, which he estimated at a minimum of 5,000 industrial users. He chose the second.

Between the spring of 1982 and the summer of 1983 he designed and implemented Cfront, a traditional compiler front end that fully checked syntax and semantics, built an internal representation, and produced output for a code generator. The first user outside the research center, Jim Coplien at Bell Labs in Naperville, Illinois, received a copy in July 1983.

The new language was at first still called C with Classes, then, after a polite request from management, C84. People had taken to calling C with Classes "new C" and then just C, leaving the original to be called "plain C" or "old C". C84 lasted only a few months: it was ugly, and confusion would remain if people dropped the 84. Stroustrup asked for ideas and chose C++, suggested by Rick Mascitti — "short, had nice interpretations, and wasn't of the form 'adjective C'". ++ is C's increment operator, marking an evolution of C. The name was coined in the summer of 1983 and first used when it was edited into the final copy of a paper in December 1983.

October 1985: the first commercial release

According to Stroustrup's FAQ, the first version of C++ was in use inside AT&T in August 1983, and "the first commercial implementation was released October 1985" together with the first edition of The C++ Programming Language. In Cfront terms this was Release 1.0, and the language was the one that book defined.

By Stroustrup's reckoning, few outside influences left traces in C++ as released in 1985: Simula gave classes; Algol 68 gave operator overloading, references and declarations anywhere in a block; BCPL gave // comments. Modula-2, Ada, Smalltalk, Mesa and Clu were considered as sources of ideas but left nothing noticeable. Compatibility with C was a major controversy, settled in the end as an agreement that there would be no gratuitous incompatibilities with ANSI C.

The feature with the greatest impact was the virtual function, borrowed from Simula. C with Classes had left it out: Stroustrup doubted he could teach people to use virtual functions, or convince them that a virtual function is as efficient in time and space as an ordinary function.

Later releases and standardisation

Cfront kept evolving. Releases 1.1 (June 1986) and 1.2 (February 1987) were mainly bug fixes; 2.0 (June 1989) added multiple inheritance; 3.0 (September 1991) added templates. The Annotated C++ Reference Manual (1990), written with Margaret Ellis, became the starting point for formal standardisation, and Stroustrup handed control of the reference manual to the ANSI C++ committee in early 1990. The first ISO standard was C++98.

For the ideas behind it, see object-oriented programming and type systems in the glossary; for its contemporaries, the programming-languages timeline. Simula's classes came from Ole-Johan Dahl and Kristen Nygaard; C came from Dennis Ritchie.