Free online C programming?

[Surpuppa]

Hi, so here is the thing, on my work computer I loaned from the company I am not allowed to download any software, and since I currently have nothing to do I was considering refreshing my skills for an upcoming re-exam. Is there a way to program C online without having to download an IDE or anything similar? Or should I go with codeacademy and skip ahead a bit? 
Edit: I guess there is no C course on codeacademy, is it available on other similiar services?

[WickedStarfish]

Have you tried this? - https://www.onlinegdb.com/online_c_compiler

or if it isn't monitored download it and uninstall it at a later date before you go back

[Unimportant]

A linux live USB stick is also a possibility.

Boot from the stick, have a fully-fledged work environment with a real compiler. Remove the USB stick when you're done and everything's back to old.

[Guest]

I’ve found online compilers for Lua & C++ so you shouldn’t have too much trouble doing that with C. As for the knowledge, there are several open source textbooks you can read for free. 

[Biggerboot]

Thenewboston "bucky" has helped me in the past.  It's not super in-depth but easy to understand.

EDIT: Sorry I misunderstood the original question, but I agree with the USB suggestions.