When with ranges and types in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if number is in the range 1 to 10 using when.

Kotlin

val number = 5
val result = when (number) {
    in [1] -> "Number is between 1 and 10"
    else -> "Number is out of range"
}

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

A0..9

B1 until 10

C10..1

D1..10

Attempts:

3 left

💡 Hint

Common Mistakes

Using '1 until 10' excludes 10, so it won't match number 10.

Using reversed ranges like '10..1' does not work as expected.

The range 1..10 includes numbers from 1 to 10 inclusive, which matches the condition.

2fill in blank

medium

Complete the code to check if the input is a String using when.

Kotlin

fun checkType(input: Any) = when (input) {
    is [1] -> "Input is a String"
    else -> "Input is not a String"
}

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

ADouble

BInt

CString

DBoolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase type names like 'string' instead of 'String'.

Checking for wrong types like Int when expecting String.

The 'is' keyword checks the type of the input. We want to check if it is a String.

3fill in blank

hard

Fix the error in the when expression to correctly check if number is in 1..5 or 6..10.

Kotlin

val number = 7
val result = when (number) {
    [1] -> "Between 1 and 5"
    in 6..10 -> "Between 6 and 10"
    else -> "Out of range"
}

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

Anumber in 1..5

Bin 1..5

C1..5

Din 1 until 5

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting 'in' keyword before the range.

Using 'number in 1..5' inside when case which is not valid syntax.

The 'in' keyword is needed before the range to check if number is inside it.

4fill in blank

hard

Fill both blanks to check if input is Int in 1..10 or String of length > 5.

Kotlin

fun describe(input: Any) = when (input) {
    is [1] -> if (input in 1..10) "Int in range" else "Int out of range"
    is [2] -> if (input.length > 5) "Long String" else "Short String"
    else -> "Unknown"
}

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

AInt

BString

CDouble

DBoolean

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up types or using wrong type names.

Forgetting to use 'is' keyword before type.

We check if input is Int or String using 'is' keyword and then apply conditions.

5fill in blank

hard

Fill all three blanks to create a when expression that returns different messages for Int ranges and String lengths.

Kotlin

fun analyze(input: Any) = when (input) {
    is [1] -> when {
        input [2] 1..5 -> "Small number"
        input [3] 6..10 -> "Medium number"
        else -> "Large number"
    }
    is String -> "String of length ${input.length}"
    else -> "Unknown type"
}

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

AInt

Bin

C!in

DDouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong type names or forgetting 'is'.

Confusing 'in' and '!in' operators.

We check if input is Int, then use 'in' and '!in' to check ranges inside nested when.