See class 9 of the Nice categories. If you claim a trademark For class 9 it includes "all computer programs and software regardless of recording media or means of dissemination, that is, software recorded on magnetic media or downloaded from a remote computer network."
Also mind the way this practically works: A company will try to register a mark in as many categories as possible.
"Scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signalling, checking (supervision), life-saving and teaching apparatus and instruments; apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling electricity; apparatus for recording, transmission or reproduction of sound or images; magnetic data carriers, recording discs; compact discs, DVDs and other digital recording media; mechanisms for coin-operated apparatus; cash registers, calculating machines, data processing equipment, computers; computer software; fire-extinguishing apparatus."
Computers programs are a part of 090373 which has a breakdown of ~100 subcategories.
There are 45 Nice classes. Being in the same top-level class is not confusingly similar. Unless you think Kik Marine Compasses and Kik Instant Messenger might be confusingly similar.
