To program the RCX brick in C, we recommend using the NQC (Not Quite C) programming language. NQC is C-like in it's syntax, and is quick and easy to learn, however it is limited by the standard firmware of the RCX brick. More information can be found at http://bricxcc.sourceforge.net/nqc.
An alternative to NQC is BrickOS. BrickOS still allows us to program the RCX brick in C (as well as C++), and it also offers some improvements over the standard firmware on the RCX brick, however, it is still in its developmental stages. More information can be found at http://brickos.sourceforge.net.
Two IDEs that we recommend using for programming the RCX in C, are MacNQC (for Mac) and Bricx Command Center (for PC). The Bricx IDE can also be used with BrickOS, LejOS, and pForth. The IDEs and source files can be found at the following links:
MacNQC - http://homepage.mac.com/rbate/MacNQC/index.html
BricxCC - http://bricxcc.sourceforge.net
BrickOS - http://brickos.sourceforge.net
