Non-nullable types by default in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a non-nullable integer variable named age with value 30.

Kotlin

val age: Int = [1]

Drag options to blanks, or click blank then click option'

A30

Bnull

C"30"

D30L

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning null to a non-nullable type causes a compilation error.

Using quotes around numbers makes them strings, not integers.

The variable age is declared as a non-nullable Int, so it must be assigned a non-null integer value like 30.

2fill in blank

medium

Complete the code to declare a non-nullable string variable name with value "Alice".

Kotlin

val name: String = [1]

Drag options to blanks, or click blank then click option'

Anull

BAlice

C"Alice"

Dalice

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string literals.

Assigning null to a non-nullable variable.

Strings must be enclosed in double quotes. Since name is non-nullable, it cannot be assigned null.

3fill in blank

hard

Fix the error in the code by completing the declaration of a non-nullable Boolean variable isActive with value true.

Kotlin

val isActive: Boolean = [1]

Drag options to blanks, or click blank then click option'

Atrue

Bnull

C"true"

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase True instead of lowercase true.

Assigning null to a non-nullable variable.

Using quotes around Boolean values.

The Boolean value true is lowercase in Kotlin and must not be in quotes. Non-nullable variables cannot be assigned null.

4fill in blank

hard

Fill both blanks to declare a non-nullable variable height of type Double with value 1.75.

Kotlin

val height: [1] = [2]

Drag options to blanks, or click blank then click option'

ADouble

B1.75

CFloat

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using Float instead of Double when the type is specified as Double.

Assigning null to a non-nullable variable.

The variable height is declared as a non-nullable Double type and assigned the value 1.75.

5fill in blank

hard

Fill all three blanks to create a non-nullable variable score of type Int, assigned the value 100, and print it.

Kotlin

val [1]: [2] = [3]
println(score)

Drag options to blanks, or click blank then click option'

Ascore

BInt

C100

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using null as value for a non-nullable variable.

Mixing up the order of variable name, type, and value.

This code declares a non-nullable integer variable score with value 100 and prints it.