Filipe Fortes, programmer and founder of Coda, once joked that debugging is like “being a detective in a crime movie” except we know exactly who did it because we’re the ones that did the programming! As we work through the puzzles in this course, it might help to picture ourselves as Sherlock Holmes, or any other famous detective trying to solve a mystery. We have found that debugging is easier to understand and more enjoyable with this mindset. With that in mind, have fun solving the brain teasers in this course—perhaps we might even learn a new trick or two.

The course contains 25 carefully designed brain teasers which will challenge us to find creative solutions. Each puzzle contains two parts. In the first part, we’ll look at a static code and guess the expected output. In the next part, we’ll have an executable code to run the puzzle and see the output. After that, we’ll find out why the program produces the result and how similar issues might affect the code in other programs.