When as expression returning value in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign the correct string based on the number using when expression.

Kotlin

val result = when (number) {
    1 -> "One"
    2 -> "Two"
    else -> [1]
}

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

A"Other"

B"Unknown"

C"Zero"

D"None"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to return a string in else branch.

Using a number instead of a string in else.

The else branch must return a string value. "Other" is the correct default string here.

2fill in blank

medium

Complete the when expression to return "Even" for even numbers and "Odd" for odd numbers.

Kotlin

val parity = when {
    number % 2 == 0 -> [1]
    else -> "Odd"
}

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

A"Odd"

B"Zero"

C"Even"

D"None"

Attempts:

3 left

💡 Hint

Common Mistakes

Returning "Odd" for even numbers.

Using numbers instead of strings as return values.

The first condition checks if number is even, so it should return "Even".

3fill in blank

hard

Fix the error in the when expression to correctly return a string for the input.

Kotlin

val description = when (input) {
    is String -> "Text"
    is Int -> [1]
    else -> "Unknown"
}

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

Ainput.toString()

Binput.length

Cinput

D"Number"

Attempts:

3 left

💡 Hint

Common Mistakes

Returning input directly which is an Int, causing type mismatch.

Returning input.length which is invalid for Int.

The when expression must return a string. "Number" is the correct string for Int input.

4fill in blank

hard

Fill both blanks to create a when expression that returns the length of a string or zero otherwise.

Kotlin

val length = when (val value = input) {
    is String -> [1]
    else -> [2]
}

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

Avalue.length

B0

Cinput.length

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using input.length instead of value.length inside when.

Returning null instead of 0 for else case.

For a String input, return its length. Otherwise, return 0.

5fill in blank

hard

Fill all three blanks to create a when expression that returns a message based on the score value.

Kotlin

val message = when {
    score >= [1] -> "Excellent"
    score >= [2] -> "Good"
    else -> [3]
}

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

A90

B60

C"Try again"

D"Average"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the threshold values.

Returning a number instead of a string in else.

Scores 90 or above get "Excellent", 60 or above get "Good", else "Try again".