Lecture 20 Coding Standards Tools for Debugging 1

1. Lecture 20 Coding Standards Tools for Debugging 1

2. Coding Standards Or How to Pound all of your odd-shaped programmers into a one size fits all hole

3. I think there may be a bug in Joe’s Code - Please Fix • func GreenEggsNHam(Not SamIAm, Green EggsNHam) • foreach Green TryThem in SamIAm • do EatThem(TryThem) = false • NotInACarNotOnABus(EggsNHam) • func NotInACarNotOnABus(Green EggsNHam) • EatThem(EggsNHam) = true • NotOnAPlane(EggsNHam) • foreach NotLikeThem SamIAm of EggsNHam do • if not EatThem(SamIAm) then • NotInACarNotOnABus(SamIAm) • IDoNotLikeThem(EggsNHam)

4. Joe’s Code Following a Sane Coding Standard . . . • func DepthFirstSearch(graph G, vertex v) • foreach vertex w in G • do Encountered(w) = false • RecursiveDFS(v) • func RecursiveDFS(vertex v) • Encountered(v) = true • PreVisit(v) • foreach neighbor w of v do • if not Encountered(w) then • RecursiveDFS(w) • PostVisit(v)

5. What are Coding Standards • Coding standards are guidelines for code style and documentation. • The dream is that any developer familiar with the guidelines can work on any code that followed them. • Standards range from a simple series of statements to involved documents.

6. Areas Typically Covered • Program Design • Naming Conventions • Formatting Conventions • Documentation • Possibly Even Licensing

7. Why Have Coding Standards • Greater consistency between developers • Easier to develop and maintain • Saves time and money

8. Prime Directive • Document every time you violate a standard. • No standard is perfect for every application, but failure to comply with your standards requires a comment

9. Ambler’s Law of Standards • Industry Standards > organizational standards > project standards > no standards • The more commonly accepted a standard the easier it is for team members to communicate • Invent standards when necessary, but don’t waste time creating something that you won’t be able to use later. • All languages have recommended coding standards available. It is well worth your effort to find and use industry standards • Push for organizational standards whenever possible

10. Good Coding Style • Names • Use full English descriptors • Use mixed case to make names readable • Use abbreviations sparingly and consistently • Avoid long names • Avoid leading/trailing underscores • Documentation • Document the purpose of every variable • Document why something is done not just what

11. Accessors • use getVar() and setVar() functions on all class variable unless class is being used solely as a data structure (OOP) • Member Functions Documentation • What and why member function does what it does • Parameters / return value • How function modifies object • Preconditions /Postconditions • Concurrency issues • Restrictions • Internal Documentation • Control Structures • Why as well as what the code does • Difficult or complex code • Processing order

12. Three Rules • Coding standards needn’t be onerous - find a standard that works for your team. • Standardize early - the effort to bring your old work into the standard will be too great otherwise. • Encourage a culture where standards are followed.

13. Examples of Coding Standards • http://www.ambysoft.com/javaCodingStandards.html • http://www.swtech.com/java/codestd/ • http://ccs.hst.nasa.gov/ccspages/policies/standards/coding_standards.html • http://www.scriptics.com/doc/styleGuide.pdf