Kotlin - Null Safety
Which of the following is a valid use of the safe cast operator as? in Kotlin?
Which of the following is a valid use of the safe cast operator as? in Kotlin?
easy📝 Conceptual Q2 of 15
Step-by-Step Solution
Solution:
Step 1: Check type compatibility with safe cast
The safe castas?returns a nullable type, so the variable must accept nulls.Step 2: Analyze options
Only val num: Int? = obj as? Int declares a nullable Int, matching the safe cast's nullable return type.Final Answer:
val num: Int? = obj as? Int -> Option BQuick Check:
Safe cast returns nullable type = B [OK]
Quick Trick: Safe cast result must be nullable type variable [OK]
Common Mistakes:
MISTAKES- Assigning safe cast result to non-nullable variable
- Using unsafe cast syntax with safe cast operator
- Confusing nullable and non-nullable types
Master "Null Safety" in Kotlin
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