Good Programming Style

• Write Clearly - don't be too clever - don't sacrifice clarity for efficiency.
• Say what you mean, simply and directly.
• Be sparing with temporary variables.
• Parenthesize to avoid ambiguity.
• Use library functions.
• Replace repetitive expressions by calls to a common function.
• Choose variable names that won't be confused.
• If a logical expression is hard to understand, try transforming it.
• Choose a data representation which makes the program simple.
• Don't patch bad code - rewrite it.
• Write and test a big program in small pieces.

• Test input for plausibility and validity.
• Identify bad input - recover if possible.
• Make sure input doesn't violate the limits of the program.
• Terminate input by end-of-file or marker, not by count.
• Make input easy to prepare and output self-explanatory.

• Make sure all variables are initialized before use.
• Watch out for off-by-one errors.
• Make sure your program "does nothing" gracefully.
• Test programs at their boundary values.
• Check some answers by hand.
• 10.0 times 0.1 is hardly ever 1.0.
• Don't compare floating point numbers solely for equality.

• Make it right before you make it faster.
• Make it fail-safe before you make it faster.
• Make it clear before you make it faster.
• To make it faster, change the algorithm not small details in the code.
• Actually test code to see how fast it is.

• Make sure comments and code agree.
• Use variable names that mean something.
• Format a program to help the reader understand it.
• Don't just echo code in comments - make every comment meaningful.
• Document your data structures.
• Don't over comment.
• Don't comment bad code - rewite it.

• Use recursive procedures for recursively defined data structures.
• Use data arrays to avoid repetitive control sequences.

From: The Elements of Programming Style, Brian Kernighan and P. J. Plauger,McGraw-Hill Book Company, New York, 1974.

Quoted by Anthony Kapolka of Wilkes University

Requoted by X. Meng with permission