Editing Computer program (section)

===Data flow analysis===
[[File:Sandwich data flow diagram.pdf|thumb|A sample function-level data-flow diagram]]
''Data flow analysis'' is a design method used to achieve modules of ''functional cohesion'' and ''data coupling''.<ref name="se-ch9-258">{{cite book
  | last = Schach
  | first = Stephen R.
  | title = Software Engineering
  | publisher = Aksen Associates Incorporated Publishers
  | year = 1990
  | page = 258
  | isbn = 0-256-08515-3
}}</ref> The input to the method is a [[data-flow diagram]]. A data-flow diagram is a set of ovals representing modules. Each module's name is displayed inside its oval. Modules may be at the executable level or the function level.

The diagram also has arrows connecting modules to each other. Arrows pointing into modules represent a set of inputs. Each module should have only one arrow pointing out from it to represent its single output object. (Optionally, an additional exception arrow points out.) A [[Daisy chain (electrical engineering)|daisy chain]] of ovals will convey an entire [[algorithm]]. The input modules should start the diagram. The input modules should connect to the transform modules. The transform modules should connect to the output modules.<ref name="se-ch9-259">{{cite book
  | last = Schach
  | first = Stephen R.
  | title = Software Engineering
  | publisher = Aksen Associates Incorporated Publishers
  | year = 1990
  | page = 259
  | isbn = 0-256-08515-3
}}</ref>