In object-oriented design, what outcome is achieved by high cohesion and low coupling?

In object-oriented design, what outcome is achieved by high cohesion and low coupling?

• A. Better runtime performance
• B. Increased memory usage
• C. Maintainability and testability
• D. Longer development time

Answer: (C)

High cohesion and low coupling make software easier to maintain and test. Cohesion means a class or module has a clear, single purpose and all of its parts contribute to that purpose. When a component is cohesive, it’s simpler to understand, reuse, and modify because every piece has a related responsibility. Low coupling means modules depend on each other as little as possible, typically interacting through clean, stable interfaces rather than concrete implementations. This minimizes the risk that a change in one part will ripple through unrelated parts. Together, these characteristics reduce the impact of changes, enable testing of components in isolation, and make the codebase more adaptable over time. Those benefits map directly to maintainability and testability. The other options aren’t guaranteed outcomes of high cohesion and low coupling: runtime performance and memory usage aren’t dictated by these design goals, and longer development time is not a necessary result—the upfront design effort can even reduce overall time by avoiding later refactors.

High cohesion and low coupling make software easier to maintain and test. Cohesion means a class or module has a clear, single purpose and all of its parts contribute to that purpose. When a component is cohesive, it’s simpler to understand, reuse, and modify because every piece has a related responsibility. Low coupling means modules depend on each other as little as possible, typically interacting through clean, stable interfaces rather than concrete implementations. This minimizes the risk that a change in one part will ripple through unrelated parts.

Together, these characteristics reduce the impact of changes, enable testing of components in isolation, and make the codebase more adaptable over time. Those benefits map directly to maintainability and testability.

The other options aren’t guaranteed outcomes of high cohesion and low coupling: runtime performance and memory usage aren’t dictated by these design goals, and longer development time is not a necessary result—the upfront design effort can even reduce overall time by avoiding later refactors.