A History of the C Languages By: Kevin Burnette

Outline History  Ancestor languages overview Development of C Development of C++

Where it all began Combined Programming Language – CPL Basic Combined Programming Language – BCPL B

What’s new in B += and -= operators were introduced to the language ++ and -- operators were invented.

From B to C New B - NB  Dennis Ritchie of Bell Labs created an extend version of B in  Added int, and char types, arrays of them and pointers to them and rewrote the compiler to create PDP-11 instructions.  NB created programs small and fast enough to compete with assembly written programs.

Questions of design These questions were asked in designing structure types.  “Where could the compiler hide the pointer to name that the semantics demanded?” (Ritchie 8)  “Even if structures were thought of more abstractly, and the space for pointers could be hidden somehow, how could I handle the technical problem of properly initializing these pointers when allocating a complicated object, perhaps one that specified structures containing arrays containing structures to arbitrary depth?” (Ritchie 8)

Answer: The solution eliminated the materialization of the pointer in storage, and instead caused the creation of the pointer when the array name is mentioned in an expression. This provided a large jump in the evolution between typeless BCPL and C.

More Innovation – Type Structure “The central notion I captured from Algol was a type structure based on atomic types (including structures), composed into arrays, pointers (references), and functions (procedures).” (Ritchie 8)

C is officially born “After creating the type system, the associated syntax, and the compiler for the new language, I felt that it deserved a new name; NB seemed insufficiently distinctive. I decided to follow the single-letter style and called it C, leaving open the question whether the name represented a progression through the alphabet or through the letters in BCPL.” (Ritchie 9)

Further Development Preprocessor  The preprocessor was originally added as an optional component  First version only provided file including and simple string replacement  Idea was taken from BCPL and PL/I

C with Classes Work began in 1979 in attempt to analyze the UNIX kernel to see if it could be distributed over a network Bjarne Stroustrup begin creating the tools he needed based on his experience with Simula

C++ Between 1982 and 1984 Stroustrup began to think of C with Classes as a separate language instead of an addition to C. Version 1.0 was released in 1985 and C++ was officially named.

Code Examples GET "LIBHDR" MANIFEST $( BOTTLES = 99 $) LET START() BE $( LET BEERS(N, S) BE $( TEST N = 0 THEN WRITEF("No more bottles") ELSE WRITEF("%N bottle%S", N, (N = 1) -> "", "s") WRITEF(" of beer%S", S) $) FOR I = BOTTLES TO 1 BY -1 DO $( BEERS(I, " on the wall, ") BEERS(I, ".*NTake one down, pass it around.*N") BEERS(I - 1, " on the wall.*N") $) FINISH $) From:

Sources “BCPL.” Wikipedia: The Free Encyclopedia Wikipedia. 7 Apr “Combined Programming Language.” Wikipedia: The Free Encyclopedia Wikipedia. 7 Apr Ritchie, Dennis. “The Development of the C Language.” History of Programming Languages-II. Ed. T.J. Bergin, Jr. and R. G. Gibson, Jr. ACM Press (New York) and Addison-Wesley (Reading, Mass), 1996; ISBN Stroustrup, Bjarne. “A History of C++: ” History of Programming languages. Ed. T.J.Bergin and R.G. Gibson, Jr. ACM Press (New York) and Addison-Wesley (Reading, Mass), 1996; ISBN