Problem Statement
What metrics or indicators might you use to measure coupling and cohesion in a software system? How would these metrics inform your decision-making and refactoring strategy?
Explanation
To measure coupling and cohesion you might use metrics such as number of module dependencies, fan-in/fan-out values (how many modules call this module and how many this module calls), coupling-between-objects (CBO), Lack of Cohesion in Methods (LCOM) for classes, and others. /n/n For example if a class has many unrelated methods and fields, a high LCOM value signals low cohesion. If a module has many outward calls and high fan-out, it signals high coupling. /n/n These metrics inform refactoring: modules with poor design metrics are candidates for decomposition, abstraction, interface introduction or removal of unnecessary dependencies. Discussing metrics in an interview shows you understand both theory and practice of design quality.
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