These are small coding challenges for the SPARTA booth at Le Hack 2019.
These programs contain some bugs (both deliberate and accidental) and it is your task to find and fix them. Also, please indicate the tool(s) you used to find them, if any.
Note: the challenge is over! Some bugs were found and applied to the code, but more bugs still remain. You can try to find them for fun (but no profit)!
Note: challenge #5 had no participants and was saved for later. Thus the challenge was removed from the Git history, which was rewritten.