code-style.org

C/C++ Code Style

Rules

• Use 4 spaces for indentation. Don’t use tabs.
• Use 100-character column width.
• Use snake_case for the names (not camelCase).
• All macro names must be in UPPERCASE.
• Use 1TBS (the one true brace style).

  int main(int argc, char *argv[])
  {
      if (argc > 2) {
          printf("too many args\n");
      } else {
          printf("too little args\n");
      }
  
      return 0;
  }
      

  Note brace position. The braces in control structures are required even for a single statement.

• The pointer star must be aligned to the variable name:

  int *x;
      

• Labels must be indented one level less than the normal indentation (except for case labels):

  int main(int argc, char *argv[])
  {
      switch (argc) {
          case 3:
              printf("hi\n");
  
          default:
              goto fail;
      }
      return 0;
  
  fail:
      return 1;
  }
      

• Prefer double-indent instead of alignment in conditions and argument lists:

  int my_function(int param1, int param2,
          int param3, int param4)
  {
      if (param1 > 3 && param2 > 3 &&
              param3 > 3 && param4 > 3) {
          return param1 + param2 + param3 +
              param4;
      } else {
          return 0;
      }
  }
      

• Don’t allow trailing spaces or lines.

Editor configurations

Emacs

(require 'whitespace)
(setq-default whitespace-style '(face
                                 tab-mark
                                 empty
                                 trailing
                                 lines-tail))
(global-whitespace-mode t)

(c-add-style "kaa"
             '("k&r"
               (whitespace-line-column . 100)
               (indent-tabs-mode . nil)
               (c-basic-offset . 4)
               (c-label-minimum-indentation . 0)
               (c-offsets-alist . ((case-label . +)
                                   (arglist-intro . ++)
                                   (arglist-cont-nonempty . ++)
                                   (inextern-lang . 0)))))

(setq c-default-style "kaa")