C Programming Language Style and Conventions

• write it once, and only once
  • so that modifications require one change, in one place
  • because less code is better code
• use only -1, 0, and 1 as constants
  • #define everything else to be meaningful
  • even better - use enum for constants
• boolean != NULL != 0 != ‘\0’
  • keep your data types separate
• check and validate input (including excess)
  • don't ignore any user input
• don’t modify function arguments
  • copy the arguments to temporaries if needed
• fopen/fclose malloc/free at same level
  • don't hide file open/close in functions
  • don't hide malloc and free in functions
• check function return codes
  • if it can fail, test it
  • write cover functions to avoid duplicating the testing code
• read input in only one place
  • handle EOF properly
• avoid global variables
  • because you never know who changes them
  • use the static keyword wherever possible
• print really good error messages
  • not "too big"; instead: "bigger than %d bytes"
• get the code right first, then optimize
• put short, explanatory comments at the start of blocks of C code

Ian D. Allen CST8152 Home Page