600.107: Introduction to Programming (in Java)

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Programming Style

This page describes the minimum rules of programming style that you are required to follow. If you violate these guidelines, the grader can refuse to look at your code, resulting in no points for you. We reserve the right to add new requirements as the semester progresses, but we'll always announce an update on the course mailing list before it goes into effect.

• Indent your code consistently using 2 or 4 spaces (not tabulators) for each nesting level; where you put braces is really up to you, just put them consistently as well. And please always put braces as part of instructions like if and while, don't ever leave them out.
• (Starting Assignment 1) Also make sure that your lines are at most 75 characters long, not any longer than that!
• Follow the standard conventions for identifiers: packages are all.lower.case, classes are MixedUpperCase and start with upper case, variables, functions, and procedures are mixedUpperCase but start with lower case, constants are ALL_CAPS with underscores if needed; functions often (but not always) start with adjectives, procedures often (but not always) start with verbs. Also, the larger the scope of an identifier, the longer and more descriptive it should be; using i inside a procedure is fine, using i inside a class is not a good idea.
• Don't compare boolean expressions to true or false: They are boolean already, no additional comparison needed, ever.
• Once javadoc is introduced, have at least one comment for each class or interface and one comment for each method. Follow the usual guidelines for writing these. They don't have to be essays but should be complete enough and clearly worded. Comments inside your code should add information to the code, not repeat obvious things. Consider a comment for the purpose of each variable as well, the larger the scope of a variable is the more important such a comment about will be. And don't contradict your code!
• (Starting Assignment 2) When hacking loops, avoid break and continue instructions as far as possible. If you think you need one, think again. If you still think you need one, include a comment that explains why. For methods, please avoid multiple return instructions as far as possible. However, since these are usually more benign (as long as your methods are not too long), there's no need to think as hard about them (but defending them in a comment is still encouraged).
• (Starting Assignment 2) Do not leave "magic numbers" like 9.81 and 42.7 in your code, introduce useful names for them in some final declaration. Numbers that are okay to have are really basic ones like 0, 1, 2, and similar.

Note that you're welcome to follow the official Code Conventions for the Java Programming Language as published by Sun instead of our minimal conventions, just make sure you tell us which conventions you follow. If in doubt, the minimum conventions are recommended because they are simpler.