No, C has no classes per se, only C++ (which started out as "C with classes" back then...). But you can use the standard C library in C++ code, even if it is often not considered good practice (where C++ has its own, higher level constructs, e.g. cout
vs printf
).
You can sort of emulate the behaviour of classes, inheritance and virtual functions in C too, but it's not worth the pain.
You should probably buy/get your ex classmate a C programming book :-)