October 2025
Intermediate to advanced
100 pages
2h 27m
English
Content preview from Kotlin Brain Teasers
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Discussion
The person who wrote this program has forgotten about Kotlin’s operator precedence rules, and the oversight has resulted in a bug. We can guess that the goal is to take the bonus value and add the salary to it—with 0 acting as a fallback option that would only be used if bonus was null.
That interpretation is backed up by the names of the variables as well as by your intuitive left-to-right reading of the program, which can make the bug hard to spot. But that’s not how Kotlin interprets this code. In reality, 0 + salary is grouped together and evaluated first.
Thanks to that unintended grouping, the overall result is just the value ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.