Stuff like that is what various completion options are for. Ideally you only type crap like that out once, and for that typing with your left pinky on shift is sufficient for me.
Funny enough, I just installed a vim plugin that gives a mapping for converting variables between camelCase, snake_case, MixedCase, and UPPER_CASE. The plugin is vim-abolish by Tim Pope.
(This isn't really relevant to your post, just funny)
C identifiers like AUDCLNT_E_UNSUPPORTED_FORMAT.