Graphics for Windows and Linux

I have taken on a small project that requires me to install graphics onto a text based game.
The game is prety simple its just two tanks trying to kill each other.
The text based game engine is alredy made and working fine.

But now i want to add graphics and sounds to the game.
instead of little ascii characters shooting periods at each other.

I need a library or something that will work on both WIndows compilers and linux compilers.

Since this will be given to students who will develop their own AI. I dont want to limit them to using just one compiler.

i wanted to use Direct X but i found out it does not work well in linux or work at all for that matter.

So i need a graphics library and the include files i will need in order to start me off. I can learn of the commentations and things like that off the code but i just neeed the library.


so if you can just give me the files i need

#include <library name>

if i need a seperate library for sound then that would also be apreciated

to include sound please give me an example of the function call becouse im not to familiar with sound still.

or whatever i need to put in my code

and if i need to download something where i can get it

thank you.