AP CSA Unit 4 Day 22: Arraylist Remove All Even Numbers
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Unit 4, Data Collections • Cycle 2
Day 22 Advanced Practice • Harder Difficulty
Focus: ArrayList Remove All Even Numbers
Hard
ArrayList Remove All Even Numbers
Advanced Practice Question
Format: ArrayList Remove All Even Numbers
What is the correct way to remove all even numbers from this ArrayList?
What is the correct way to remove all even numbers from this ArrayList?
ArrayList nums = new ArrayList<>();
nums.add(1);
nums.add(2);
nums.add(3);
nums.add(4);
nums.add(5);
// Which approach correctly removes all even numbers?
Difficulty: Hard |
Topic: ArrayList Remove All Even Numbers |
Cycle: 2 (Advanced)
Why This Answer?
Option A skips elements after removal (index shift). Option C causes ConcurrentModificationException (can't modify during for-each). Option D doesn't actually remove. Option B iterates backward, avoiding index issues.
Common Mistake
Watch Out!
Using forward iteration when removing, causing skipped elements due to index shifts.
AP Exam Strategy
To remove during iteration: iterate BACKWARD so indices of unchecked elements don't shift.
Master This Topic
This Cycle 2 HARD question tests arraylist remove all even numbers. Review Unit 4 concepts to build mastery of data collections.
- Understanding arraylist remove all even numbers
- Tracing code execution accurately
- Avoiding common pitfalls
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