Summary

In this chapter, we have explored several principles to achieve a clean design. Understanding that the code is part of the design is key to achieving high-quality software. This and the following chapter are focused precisely on that.

With these ideas, we can now construct more robust code. For example, by applying DbC, we can create components that are guaranteed to work under their constraints. More importantly, if errors occur, this will not happen out of the blue, but instead, we will have a clear idea of who the offender is and which part of the code broke the contract. This compartmentalization is clear to effective debugging.

 

Along similar lines, each component can be made more robust if it defends itself from malicious intent or incorrect input. Although this idea goes in a different direction from design by contract, it might complement it very well. Defensive programming is a good idea, especially for critical parts of the application.

For both approaches (design by contract...