CHAPTER 7 : File Layout

PART 3 : LAYOUT

CHAPTER 7 : File Layout
7.1 Layout of directories
7.2 Division of files
7.3 Considerations for File Layout
7.4 Header files
7.5 Layout of Data files
7.6 Layout of Code files
7.7 Summary

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7.7  Summary

• Aim to keep the number of files in directories that will regularly scanned down to one or two screenfuls (ie. about 50 files).
• Structure directories by file type/functional area.

• Organize files to ease navigation and minimize scope.
• Use functional cohesion to group similar items.
• Use one public function per file, plus the private functions it calls. Allow more public functions only if they share private functions.
• Use pagebreaks in files to maximize the amount of related information on one page (ie. at start of major sections and functions).
• Keep file length within about 20 pages or 1000 lines.
• Define a template for each file type to help usage of a standard layout.
• Order files by:
  • Context then definition
  • External items then internal items
  • Public items then private items
  • Name alphabetic order (if no better method)
• Put a file header comment at the start of every file
• Use page breaks to put as much of one subject on one page at once.
• Keep file width to 80 characters or less.
• Work around default tab setting rather than change it and confuse those who didn't change it.
• Identify files with a string constant.

Header files:

• Split header files to reflect the code files they serve.
• Don't reserve memory in header files.
• Minimize header file interdependency.
• Use header files to keep data declarations and their context together
• Layout header files to reflect the systems they serve.

Data files:

• Lay out data files to reflect the systems they serve.
• Be careful to match external declarations with the global data.

Code files:

• Group '#include's by scope.
• Separate external items and internal, private items.
• Put replacement items which are used once near their actual use.
• Put private function declarations at the start of the file, to form a 'contents list'.
• Sort functions by a standard scheme, eg. first by public/private, then by alphabetic name order.
• Keep function length to within one or two pages (or 100 lines).

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