Code Complete: A closer examination (Chapter 5)

Chapter 5: Design in Construction

What are design challenges?

Design challenges are the various problems that designers encounter when designing software.

  1. Design is a wicked problem — a problem in which the solution has to fail so that one can learn from the failure and come up with a better solution
  2. Design is a sloppy process — It is hard to know when the design is good enough
  3. Design is about trade-offs and priorities — It is important to strike a balance between competing design characteristics
  4. Design is non-deterministic — There are several solutions and approaches when designing software
  5. Design is a heuristic process — It involves trial and error

What is software complexity and how do we attack it?

The author defines software complexity as when a software grows so big that no one knows how changes to a particular piece of code might affect other areas of code and functionality.

What are the levels of design?

The author dives deep into the various levels of design which include the software system, division into subsystems, division into classes within packages, division into data and routines within classes, and internal routine design.

What are heuristics in design?

  1. Find real-world objects — Identifying objects, their attributes, and their relationships with other objects
  2. Form consistent abstractions — You are allowed to take a simpler view of a complex concept
  3. Encapsulate implementation details — You are not allowed to look at the details of the complex concept.
  4. Inherit — The idea that you can open and close a door regardless of what it is made of
  5. Information hiding — Hiding the inner workings of a house
  6. Keep coupling loose — Making modules as independent of other modules as possible, just like the wagons on a train
  7. Look for common design patterns — Most problems are similar or mutations of past problems

How do we handle change in design?

A good way according to the author is to identify the areas likely to change and isolate them.

What are design practices?

The author introduces us to a new set of heuristics that produce good designs. These include:

  1. Iteration — Involves cycling through design attempts as you inspect their low-level and high-level views.
  2. Divide and conquer — Divide the program into different areas of concern, and then tackle each of those areas individually
  3. Top-Down and Bottom-Up Design Approaches — Involves starting from either generalities or specifics
  4. Experimental prototyping — You can’t really come up with a problem until you have actualized it.
  5. Collaborative design — Bouncing some ideas with someone else

Conclusion

The author has done a good job of explaining the design process during software construction. However, I felt like even though the design is a huge topic, the author could have simplified most of the topics a little. Regardless, I learned a lot about heuristics and how they can be used for better software design.

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