Kotlin - Collections Fundamentals
What will be the output of this Kotlin code?
val numbers = mutableSetOf(1, 2, 3) numbers.add(2) numbers.add(4) println(numbers)
What will be the output of this Kotlin code?
medium📝 Predict Output Q13 of 15
Step-by-Step Solution
Solution:
Step 1: Understand mutableSetOf and add behavior
The set starts with 1, 2, 3. Adding 2 again does nothing because sets ignore duplicates. Adding 4 adds a new element.Step 2: Determine final set contents
After additions, the set contains 1, 2, 3, and 4.Final Answer:
[1, 2, 3, 4] -> Option DQuick Check:
Sets ignore duplicates, so 2 is not added twice [OK]
Quick Trick: Adding duplicates to sets does nothing [OK]
Common Mistakes:
MISTAKES- Expecting duplicates to appear in output
- Confusing set print format with list
- Thinking add returns error on duplicates
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