Checklist for Code Reviews

Checklist for Code Reviews

There is only one purpose in the whole of life - Education.
~Swami Vivekananda


  • Does the code completely and correctly implement the detailed design?
  • Does the code conform to any pertinent coding standards?
  • Is the code well-structured, consistent in style, and consistently indented?
  • Are there any uncalled or unneeded procedures or any unreachable code?
  • Are there any leftover stubs or test routines in the code?
  • Can any code be replaced by calls to external reusable components or library functions?
  • Are there any blocks of repeated code that could be condensed into a single procedure?
  • Is storage use efficient?
  • Are symbolics used rather than “magic number” constants or string constants?
  • Are any modules excessively complex, so should be restructured or split into multiple routines?


  • Is the code clearly and adequately documented with an easy-to-maintain commenting style?
  • Are there any inconsistencies between code and comments?


  • Are all variables properly defined and given meaningful, consistent, and clear names?
  • Do all assigned variables have proper type consistency or casting?
  • Are there any redundant or unused variables?

Arithmetic Operations

  • Does the code avoid comparing floating-point numbers for equality?
  • Does the code systematically prevent rounding errors?
  • Does the code avoid additions and subtractions on numbers with greatly different magnitudes?
  • Will all mixed-mode arithmetic operations give the correct results? Are type conversions needed?

Loops and Branches

  • Are all loops, branches, and logic constructs complete, correct, and properly nested?
  • Are the most common cases tested first in IF- -ELSEIF chains?
  • Are all cases covered in an IF- -ELSEIF or CASE block, including ELSE or DEFAULT clauses?
  • In C, does the end of each case in a CASE statement have a break?
  • Does every switch statement have a default?
  • Are loop termination conditions obvious and invariably achievable?
  • Are indexes or subscripts properly initialized, just prior to the loop?
  • Can any statements that are enclosed within loops be placed outside the loops?
  • Does the code in the loop avoid manipulating the index variable or using it upon exit from the loop?

Defensive Programming

  • Are indexes, pointers, and subscripts tested against array, record, or file bounds?
  • Are imported data and input arguments tested for validity and completeness?
  • Are divisors tested for zero or noise?
  • Are all output variables assigned?
  • Are the correct data operated on in each statement?
  • Is every memory allocation deallocated?
  • Are timeouts or error traps used for external device accesses?
  • Are files checked for existence before attempting to access them?
  • Are all files and devices are left in the correct state upon program termination?
Copyright © 1999 by Karl E. Wiegers. Permission is granted to use, modify, and distribute this document.