I am in the situation where I may have the opportunity to teach C to some students. The University wants to teach them pure c, not c++, to keep the advanced c++ course separate.
Since c++ is derived from c, is there an official "c rulebook" which contains all the features of c, but none of the c++ features? The reason I want to know is so I can look up what I need to teach the students.
I once saw a (2000 page?) manual on the c++ standard. Does such a thing exist for c, even if it is 20/30 years old by now?
EDIT: I should point out I know C/C++ quite well having been teaching myself for 3 years. The only thing I don't know is what things are "officially" C and what things are "officially" C++. This is what I aim to learn so I can give the other students a better education than I could give myself.
You're looking for a C standard. Since the standards bodies fund themselves through the sale of standard publications, you can't get the final version. However, there are many copies of C draft standards out there which are good enough for your purposes.