Editing Computer program (section)

===Cohesion===
The levels of cohesion from worst to best are:<ref name="se-ch8-220">{{cite book
  | last = Schach
  | first = Stephen R.
  | title = Software Engineering
  | publisher = Aksen Associates Incorporated Publishers
  | year = 1990
  | page = 220
  | isbn = 0-256-08515-3
}}</ref>

* ''Coincidental Cohesion'': A module has coincidental cohesion if it performs multiple functions, and the functions are completely unrelated. For example, <code>function read_sales_record_print_next_line_convert_to_float()</code>. Coincidental cohesion occurs in practice if management enforces silly rules. For example, "Every module will have between 35 and 50 executable statements."<ref name="se-ch8-220"/>
* Logical Cohesion: A module has logical cohesion if it has available a series of functions, but only one of them is executed. For example, <code>function perform_arithmetic( perform_addition, a, b )</code>.
* ''Temporal Cohesion'': A module has temporal cohesion if it performs functions related to time. One example, <code>function initialize_variables_and_open_files()</code>. Another example, <code>stage_one()</code>, <code>stage_two()</code>, ...
* ''Procedural Cohesion'': A module has procedural cohesion if it performs multiple loosely related functions. For example, <code>function read_part_number_update_employee_record()</code>.
* ''Communicational Cohesion'': A module has communicational cohesion if it performs multiple closely related functions. For example, <code>function read_part_number_update_sales_record()</code>.
* ''Informational Cohesion'': A module has informational cohesion if it performs multiple functions, but each function has its own entry and exit points. Moreover, the functions share the same data structure. Object-oriented classes work at this level.
* ''Functional Cohesion'': a module has functional cohesion if it achieves a single goal working only on local variables. Moreover, it may be reusable in other contexts.