A good tactic may be to teach D instead. It's rather close to C (especially with the -betterC flag which disables among other things the garbage collector) but

A good tactic may be to teach D instead. It's rather close to C (especially with the -betterC flag which disables among other things the garbage collector) but fixes some of the more egregious flaws. No spiral rule. Proper modules. No preprocessor (but CTFE and mixins instead). It stays close enough to C that undefined behavior exists but far enough away to avoid nasal demons.