Student Debugging Bloopers

Or, "How I debug student projects without leaving my office".

Computers do exactly what you tell them to do therefore logic is often your best tool when debugging. Logic will dictate that certainly possibilities exist. Then you look at the likelihood and predict one of the top two or three possibilities. This file has some nice examples that embarrass students. No matter how much you want to believe something, let reality rule the day.

• Student comes to office saying that resin can't write to a log file. I say "permissions issue." They look at me funny. I say "must not be running as root". Student: "yes, it is." I say, it cannot be. Root can write to any file. Sure enough, resin not running as root.
• Student says their program cannot find a file. I say "ok, so the file is not there or you don't have permission to see it." They claim it is there. I then say "well, then your program is not asking for the file in the proper way". They swear it is and claim the code is a copy of something that does work properly. Then I say "well, then you must not be running the code you think you are." Sure enough, bad CLASSPATH. Using logic, find the possibilities and then check the most likely issues in order.