Is it just me, or does this idiom sound very similar to one of the critiqued "incorrect" programming idioms in the recently analyzed breathalyzer code?
Yes; it's almost identical. It's one of the simplest digital low-pass filters you can write. Basically, it does the same thing that an analog R/C filter would do (given sufficient precision and sampling rates).
The issue with the breathalyzer code wasn't that the algorithm was incorrect, but that the programmer used the wrong algorithm.
