Free practice · single-choice · medium
Practice
Separate a side-effect boundary
Which design makes a calculation easiest to test without writing files?
Solution architecture
Focused responsibilities create visible data boundaries
- Responsibility
- One reason for each unit to change
- Naming
- Business meaning visible at call sites
- Scope
- Local state by default
- Interface
- Explicit parameters and returned values
- Side effects
- Confined to a narrow boundary
A reviewable beginner program separates validation, calculation, formatting, and side effects through explicit parameters and returned values.