String Calculator Kata

19 September 2017

Photo: Philip Estrada - Unsplash

I wrote recently about using Kata’s regularly to practice and improve your skills. I have been using them with a junior developer to support his training plan. The latest kata we have added to his practice is the String Calculator kata from Roy Osherove.

The premise of the kata is really straightforward. There are 9 steps to fully complete the kata with a time limit of 30 minutes. The aim is to define a method that accepts a string of numbers and returns an integer containing their sum. As the kata goes on you have to improve the method to handle delimiters of varying lengths.

I have created a C# based solution for the kata which can be found on Github. I attempted to commit as I implemented each test or point of the kata. If you read back through the commit history you can see the approach I took.

The important aspect of this kata is to following the steps without reading ahead. Implement your tests and only the code that you need to pass the test. You can and should refactor as you go but only to ensure you are doing the minimal amount to pass the next test.

If you’d like to discuss anything relating to the kata or my solution then as always please contact me via twitter or email.