When designing the Library Management System, what is a key trade-off when using inheritance to model different types of library items (e.g., books, magazines, DVDs) versus using composition with a common Item interface?

medium🪤 Complexity Trap Q13 of Q15

OOP & Design Patterns - Design a Library Management System - LLD with Relationships & Edge Cases

AComposition leads to code duplication but improves runtime performance due to fewer indirections

BInheritance simplifies code reuse but reduces flexibility to add new item types without modifying base classes

CInheritance allows dynamic behavior changes at runtime, while composition fixes behavior at compile time

DComposition forces all item types to share the same data fields, limiting customization

Step-by-Step Solution

Step 1: Understand inheritance trade-offs
Inheritance promotes reuse but creates tight coupling and fragile base classes.
Step 2: Why not composition causes duplication?
Composition leads to code duplication but improves runtime performance due to fewer indirections is incorrect; composition reduces duplication by delegating behavior.
Step 3: Why not inheritance allows runtime behavior changes?
Inheritance allows dynamic behavior changes at runtime, while composition fixes behavior at compile time is false; composition better supports runtime behavior changes via delegation.
Step 4: Why not composition forces shared fields?
Composition forces all item types to share the same data fields, limiting customization is wrong; composition allows flexible data encapsulation per type.
Final Answer:
Option B -> Option B
Quick Check:
Inheritance trades flexibility for reuse; composition trades reuse for flexibility.

Quick Trick: Inheritance = reuse but rigid; Composition = flexible but needs delegation [OK]

Common Mistakes:

MISTAKES

Confusing runtime flexibility between inheritance and composition
Assuming composition causes code duplication
Believing composition forces uniform data fields

Trap Explanation:

PITFALL

Options B, C, and D reflect common misunderstandings about OOP design trade-offs.

Interviewer Note:

CONTEXT

Tests candidate's grasp of OOP design principles and trade-offs in system modeling.

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More OOP & Design Patterns Quizzes

When designing the Library Management System, what is a key trade-off when using inheritance to model different types of library items (e.g., books, magazines, DVDs) versus using composition with a common Item interface?

Step 1: Understand inheritance trade-offs

Step 2: Why not composition causes duplication?

Step 3: Why not inheritance allows runtime behavior changes?

Step 4: Why not composition forces shared fields?

Final Answer:

Quick Check:

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