Why does Kotlin allow accessing properties like length directly after an is check without explicit casting?

hard📝 Conceptual Q10 of 15

Kotlin - Variables and Type System

Why does Kotlin allow accessing properties like length directly after an is check without explicit casting?

ABecause Kotlin performs smart casts after type checks

BBecause <code>is</code> operator changes the variable type permanently

CBecause Kotlin ignores type safety inside <code>if</code> blocks

DBecause <code>length</code> is a property of all types

Step-by-Step Solution

Solution:

Step 1: Understand smart casts in Kotlin
Kotlin automatically casts a variable to a specific type after a successful is check within that scope.
Step 2: Clarify why explicit cast is unnecessary
This smart cast allows direct access to properties and methods of the checked type without manual casting.
Final Answer:
Because Kotlin performs smart casts after type checks -> Option A
Quick Check:
Smart casts explain direct property access = B [OK]

Quick Trick: Smart casts save you from writing explicit casts [OK]

Common Mistakes:

MISTAKES

Master "Variables and Type System" in Kotlin

9 interactive learning modes - each teaches the same concept differently

Want More Practice?

15+ quiz questions · All difficulty levels · Free

More Kotlin Quizzes