This book's author is a self-confessed recreational runner. In my humble opinion, runners/joggers, especially when starting out (and frequently, even experienced ones), can benefit from a consistently followed run:walk pattern (the unit is minutes, typically).

The idea behind this is that running continuously is hard, especially for beginners. Often, coaches have the newbie runner follow a useful run:walk strategy; run for some given amount of time, then take a walk break for a given time period, then repeat—run again, walk again—indefinitely, or until your target distance (or time) goal is met.

For example, when a beginner runs distances of, say, 5 km or 10 km, (s)he might follow a consistent 5:2 run:walk pattern; that is, run for 5 minutes, walk for 2 minutes, keep repeating this, until the run is done. (Ultra-runners, on the other hand, might prefer something akin to a 25:5 strategy.) 

Why not write a run:walk timer application to help out both our budding and serious runners.

We shall do just that. First, though, from the viewpoint of understanding this program better, let's imagine the program is written and working—we shall give it a spin.