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Consider the Builder pattern code where the Director constructs a house with no parts (empty build). What will print(house) output after this construction?

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OOP & Design Patterns - Factory vs Abstract Factory vs Builder - When to Use Each

Consider the Builder pattern code where the Director constructs a house with no parts (empty build). What will print(house) output after this construction?

AHouse parts: Walls, Roof

BHouse parts: None

CHouse parts:

DHouse parts: Pool

Step-by-Step Solution

Solution:

Step 1: Director.construct_empty_house() does nothing
No parts are added to house.parts list.
Step 2: __str__ method returns string
Since parts list is empty, the conditional returns "House parts: None".
Final Answer:
Option B → Option B
Quick Check:
Empty parts list leads to 'House parts: None' output [OK]

Quick Trick: Empty parts list returns 'House parts: None' due to conditional [OK]

Common Mistakes:

MISTAKES

Assuming empty join returns empty string output
Expecting default parts added

Trap Explanation:

PITFALL

Candidates confuse empty list join with explicit 'None' string due to conditional.

Interviewer Note:

CONTEXT

Tests edge case handling and string representation in Builder pattern.

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