Teach strict types, tell them types are objects. Teach casts. Teach machine representation/memory/pointers. Teach memory management (malloc vs static vs alloca vs auto). Teach what .objs and .libs are. Teach symbol resolution/linking. Teach them "(*(__int64 **)&pointer) += 2" does not add 2 to the pointer but 16. Named parameters. Type promotion for extra credit. "if" doesn't need curlies if 1 line long. "switch". No sigils. Thats all I can think of. Both Perl and C are all algebra and PEMDAS.