Using stricter compiler flags is often the fastest and easiest way to catch such bugs. Here at CMU, we usually require all assignments for undergrad C/C++ courses to compile with no warnings using "gcc -ansi -pedantic -Wall -Wextra".

If you never acquire the habit of writing sloppy code and ignoring warnings, it's not even that bad. In fact, it's only the kids who already know C coming in who complain about the stricter flags.