Lecture 20 Coding Standards Tools for Debugging 1

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

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)

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)

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.

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

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

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

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

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

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

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.

Examples of Coding Standards oding_standards.htmlhttp://ccs.hst.nasa.gov/ccspages/policies/standards/c oding_standards.html