Code Quality

There are two ways of constructing a software design: one way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies. - C.A.R. Hoare
A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. - Antoine de Saint-Exupery

Coupling and Cohesion

• Definitions - Cohesion and Coupling
• Discussions on stackoverflow - 1 ; 2

Code Metrics

• Code Metrics (note: we will stick to metrics that relate to readability and maintenance rather than business or run-time efficiency metrics)
  • Number of lines of code (per method, per class)
  • Cyclomatic complexity - wikipedia
• Dependency graph example (originally from http://www.ndepend.com/SampleReports/OnNUnitNew/ComponentDependenciesDiagram.png)

Code Smells

• Code smell definition and practices for dealing with them
• Wikipedia (see list of common code smells)
• Breakdown of code smells within a class vs. code smells between classes
• Taxonomy of Code Smells

Anti-patterns

• Definition
• Wiki-books Introduction to Software Engineering/Architecture/Anti-Patterns (list with short descriptions)
• SourceMaking (sorted by category, each with a specific example on a subpage)
• Anti Patterns Catalog (list with examples and discussion pages)

Refactoring

• What is refactoring? - restructuring existing computer code without changing its external behavior
• Why Refactor?
  • Refactoring improves the design of software -without refactoring, a design will "decay" as people make changes to a software system
  • Refactoring makes software easier to understand - because structure is improved, duplicated code is eliminated, etc.
  • Refactoring helps you find bugs - refactoring promotes a deep understanding of the code at hand, and this understanding aids the programmer in finding bugs and anticipating potential bugs
  • Refactoring helps you program faster - because a good design enables progress
• When to refactor?
  • Outcomes from tools that do static code analysis
  • When you know the initial implementation was poorly planned or was rushed
  • When your boss says so
• Choosing what to refactor and how to do it
  • Files with poor metrics from code analysis
  • Code smells

Technical Debt

• Wikipedia - eventual consequences of poor software architecture and software development within a codebase
• Martin Fowler on technical debt
• Quadrants

Other thoughts and opinions on code quality, some with code samples

• All Software Sucks, but I care.
• Constructive Criticism
• Software Craftmanship + first few responses
• How not to program: http://www.dreamincode.net/forums/topic/194878-xna-animated-sprite/ - Note, this code is not bad by current practices. There is much worse code.
• Blog with a counter argument to writing clean code
• Best practices for naming conventions in C#
• Some random blog on being a professional programmer and the "discussion" and lack of comprehension in some of the comments.