First install SDL2, open up a new terminal, copy and paste the command sudo apt-get install libsdl2-dev.(if you are having issues installing, fix it on your own).
I made this game on ubuntu and didn't test it on windows, but it should work on windows since SDL is cross-platform, you may need to modify the code.
Open up a new terminal window, cd into the directory where the 'snakegame' file is. You can play the game by typing ./snakegame into the terminal
Use arrow keys to control the snake, If the snake hits the boundary or itself the game exits and displays the score on the terminal.
This is my first attempt in making a game in C, so you may find the code to be less efficent.
I used this video as a guide to make the game (https://www.youtube.com/watch?v=AaGK-fj-BAM)
If you find it hard to understand the code, your better off watching the video.
Feel free to modify and use the code ;)