The only way a programmer will be able to improve is through practice. Creating programs of different types and using different technologies usually provide a programmer with new insights into software construction. Based on this idea, a Kata is an exercise that defines some requirements or fixed features to be implemented in order to achieve some goals.

The programmer is asked to implement a possible solution and then compare it with others trying to find the best. The key value of this exercise is not getting the fastest implementation but discussing decisions taken while designing the solution. In most cases, all programs created in Kata are dropped at the end.

The Kata exercise in this chapter is about a legacy system. This is a sufficiently simple program to be processed in this chapter but also complex enough to pose some difficulties.