C was originally developed (in conjunction with the UNIX operating system) at AT&T Bell Laboratories in New Jersey in the late 1960's by Dennis Ritchie.
C++ was developed primarily by Bjarne Stroustrup at AT&T Bell Laboratories in the early 1980's.
Think C v. 4.0 and the Think Class Library are Macintosh-specific products of Symantec Corporation, 10201 Torre Avenue, Cupertino, CA 95014.