A History of the C Languages

1
A History of the C Languages

• By
• Kevin Burnette

2
Outline

• History
• Ancestor languages overview
• Development of C
• Development of C

3
Where it all began

• Combined Programming Language CPL
• Basic Combined Programming Language BCPL
• B

4
Whats new in B

• and - operators were introduced to the
  language
• and -- operators were invented.

5
From B to C

• New B - NB
• Dennis Ritchie of Bell Labs created an extend
  version of B in 1971.
• 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.

6
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)

7
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.

8
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)

9
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)

10
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

11
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

12
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.

13
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 bottleS", N, (N 1) -gt "",
  "s") WRITEF(" of beerS", 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 http//www.99-bottles-of-beer.net/language-b
  cpl-85.html

14
Sources

• BCPL. Wikipedia The Free Encyclopedia. 2006.
  Wikipedia. 7 Apr 2006. http//en.wikipedia.org/wik
  i/BCPL
• Combined Programming Language. Wikipedia The
  Free Encyclopedia. 2006. Wikipedia. 7 Apr 2006.
  http//en.wikipedia.org/wiki/Combined_Programming_
  Language
• 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 0-201-89502-1.
• Stroustrup, Bjarne. A History of C
  1979-1991. History of Programming languages. Ed.
  T.J.Bergin and R.G. Gibson, Jr. ACM Press (New
  York) and Addison-Wesley (Reading, Mass), 1996
  ISBN 0-201-89502-1.