You got this far into writing a game...why would you ever make double tapping A/D be jump? It's like some kind of weird Andy Kaufman prank on your desired audience.
....why? A significant chunk of commercial games released were done in C (maybe not 'straight", as they might plug into Lua or Python); and probably the majority of open source games were.
C is fairly straightforward to develop games in, and is one of the realms it excels in; so I have no idea why you'd feel this way.
Many, if not most, are C++ with scripting. If you’re working on something that doesn’t need scripting, pure C is totally fine.