Enum with when exhaustive check in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an enum class named Direction.

Kotlin

enum class [1] {
    NORTH, SOUTH, EAST, WEST
}

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

AMove

Bdirection

CDirections

DDirection

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or plural names for enum class.

The enum class must be named Direction with capital D as per Kotlin naming conventions.

2fill in blank

medium

Complete the when expression to check the direction variable.

Kotlin

fun describeDirection(direction: Direction): String {
    return when ([1]) {
        Direction.NORTH -> "Going north"
        Direction.SOUTH -> "Going south"
        Direction.EAST -> "Going east"
        Direction.WEST -> "Going west"
    }
}

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

Adirection

Bdir

Cd

Dmove

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name that does not exist in the function.

The parameter name is direction, so the when expression must check direction.

3fill in blank

hard

Fix the error by making the when expression exhaustive.

Kotlin

fun describeDirection(direction: Direction): String {
    return when (direction) {
        Direction.NORTH -> "North"
        Direction.SOUTH -> "South"
        Direction.EAST -> "East"
        [1] -> "West"
        // Missing WEST case causes error
    }
}

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

ADirection.WEST

BDirection.UP

CDirection.DOWN

DDirection.LEFT

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent enum values or missing cases.

The enum has a WEST value, so the when must handle Direction.WEST to be exhaustive.

4fill in blank

hard

Fill both blanks to create an exhaustive when expression without else.

Kotlin

fun describeDirection(direction: Direction): String {
    return when ([1]) {
        Direction.NORTH -> "North"
        Direction.SOUTH -> "South"
        Direction.EAST -> "East"
        [2] -> "West"
    }
}

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

Adirection

Bdir

CDirection.WEST

DDirection.UP

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or missing enum cases.

The when expression must check the variable direction and include all enum values, including Direction.WEST, to be exhaustive without else.

5fill in blank

hard

Fill all three blanks to return a message using when with exhaustive check and smart casting.

Kotlin

sealed class Result {
    data class Success(val data: String): Result()
    object Failure: Result()
}

fun handleResult(result: Result): String {
    return when ([1]) {
        is Result.Success -> "Data: [2]"
        [3] -> "Failed"
    }
}

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

Aresult

Bresult.data

CResult.Failure

Dresult.failure

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or missing the object case.

The when expression checks the result variable. For Success, it accesses result.data. For failure, it matches the singleton object Result.Failure.