Design Principles

Subject: Coding — Chapter 2.2 Design Principles Level: 1 (Recognition: MCQ, Matching, True/False with justification) Time Limit: 20 minutes Total Marks: 40

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Section A — Multiple Choice (1 mark each, 10 marks)

Choose the single best answer.

Q1. The DRY principle primarily aims to reduce: a) execution time b) duplication of knowledge/logic c) memory usage d) number of classes

Q2. "Keep It Simple" (KISS) advises a developer to: a) always use the newest design pattern b) prefer the simplest solution that works c) add configuration for every case d) avoid all abstraction

Q3. YAGNI ("You Aren't Gonna Need It") warns against: a) writing tests b) building features on speculative future needs c) refactoring d) documenting code

Q4. A class that has more than one reason to change violates the: a) Open/Closed Principle b) Single Responsibility Principle c) Liskov Substitution Principle d) Interface Segregation Principle

Q5. "Software entities should be open for extension but closed for modification" defines the: a) Dependency Inversion Principle b) Open/Closed Principle c) DRY d) KISS

Q6. If subtype objects cannot replace their base type without breaking behaviour, which principle is violated? a) Liskov Substitution b) Interface Segregation c) Single Responsibility d) YAGNI

Q7. "Clients should not be forced to depend on interfaces they do not use" is the: a) Dependency Inversion Principle b) Interface Segregation Principle c) Open/Closed Principle d) Separation of Concerns

Q8. The Singleton pattern belongs to which category? a) Structural b) Behavioral c) Creational d) Architectural

Q9. Which pattern lets an object alter its behaviour when its internal state changes, appearing to change its class? a) Strategy b) State c) Observer d) Command

Q10. The Adapter pattern is used to: a) create families of objects b) make incompatible interfaces work together c) notify observers d) undo commands

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Section B — Matching (1 mark each, 12 marks)

Match each pattern in Column X to its correct category in Column Y. Write pairs like Q11 → C.

Column X (Pattern)	Column Y (Category)
Q11. Factory Method	A. Creational
Q12. Decorator	B. Structural
Q13. Observer	C. Behavioral
Q14. Proxy
Q15. Builder
Q16. Strategy
Q17. Facade
Q18. Prototype
Q19. Command
Q20. Composite
Q21. Template Method
Q22. Abstract Factory

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Section C — True / False WITH Justification (3 marks each, 18 marks)

State True or False (1 mark) and give a one-line justification (2 marks).

Q23. Applying the Dependency Inversion Principle means high-level modules should depend on concrete low-level classes.

Q24. The Facade pattern provides a simplified, unified interface to a complex subsystem.

Q25. Following DRY sometimes conflicts with KISS when over-abstracting to remove tiny duplications.

Q26. The Observer pattern establishes a one-to-many dependency so dependents are notified automatically of state changes.

Q27. Separation of Concerns and Single Responsibility Principle are completely unrelated ideas.

Q28. The Strategy pattern hard-codes one algorithm inside the client, making it impossible to swap behaviours.

[
  {"claim":"Section A has 10 one-mark questions totalling 10 marks","code":"secA=10*1\nresult=(secA==10)"},
  {"claim":"Section B has 12 matches (Q11-Q22) totalling 12 marks","code":"qs=list(range(11,23))\nresult=(len(qs)==12 and sum(1 for _ in qs)==12)"},
  {"claim":"Section B splits evenly 4/4/4 across the three categories","code":"creational={11,15,18,22}\nstructural={12,14,17,20}\nbehavioral={13,16,19,21}\nresult=(len(creational)==4 and len(structural)==4 and len(behavioral)==4 and len(creational|structural|behavioral)==12)"},
  {"claim":"Section C is 6 questions at 3 marks = 18, and grand total is 40","code":"secC=6*3\ntotal=10+12+secC\nresult=(secC==18 and total==40)"}
]