[Solved] Consider the following Python code implem... Given a composite with two leaves named 'A' and 'B', what will be the output of iterating over the composite's iterator and collecting the names in order? | OOP & Design Patterns

OOP & Design Patterns - Iterator & Composite Pattern - Traversal Abstractions

Consider the following Python code implementing the Composite pattern with iterators. Given a composite with two leaves named 'A' and 'B', what will be the output of iterating over the composite's iterator and collecting the names in order?

A['B', 'A']

B['A', 'B']

C['root', 'A', 'B']

D['A']

Step-by-Step Solution

Step 1: Trace the stack initialization
The CompositeIterator reverses children, so stack = [leafB, leafA].
Step 2: Trace iteration order
Pop leafA first (stack now [leafB]), then leafB (stack empty). Names collected in order: 'A', then 'B'.
Final Answer:
Option B -> Option B
Quick Check:
Reversing children in stack causes correct iteration order [OK]

Quick Trick: Stack reversed children -> correct iteration order [OK]

Common Mistakes:

MISTAKES

Assuming original order without reversing stack
Including composite node name in output

Trap Explanation:

PITFALL

Reversing children in stack ensures correct iteration order, avoiding confusion.

Interviewer Note:

CONTEXT

Tests candidate's ability to mentally execute iterator code and understand traversal order.

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More OOP & Design Patterns Quizzes

Given a composite with two leaves named 'A' and 'B', what will be the output of iterating over the composite's iterator and collecting the names in order?

Step 1: Trace the stack initialization

Step 2: Trace iteration order

Final Answer:

Quick Check:

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