Kotlin Kotlin Basics

Question 1

Which keyword is used to declare an immutable variable in Kotlin?

Accepted Answer

val

Answer

In Kotlin, `val` declares a read-only (immutable) variable that cannot be reassigned after initialization.

Question 2

What is the correct way to define a nullable String in Kotlin?

Accepted Answer

String?

Answer

Appending `?` to a type in Kotlin marks it as nullable, allowing it to hold null values.

Question 3

Which of the following is the entry point of a Kotlin program?

Accepted Answer

fun main()

Answer

Every Kotlin application starts execution from the `fun main()` function.

Question 4

What does the `?.` operator do in Kotlin?

Accepted Answer

Calls the method only if the object is non-null

Answer

The safe call operator `?.` invokes a method or accesses a property only when the receiver is non-null, returning null otherwise.

Question 5

Which of the following correctly declares a Kotlin function that returns an Int?

Accepted Answer

fun add(a: Int, b: Int): Int

Answer

Kotlin functions use the `fun` keyword, with parameter types and return type separated by a colon.

Kotlin Practice Test