Throw as an expression in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to throw an exception when the number is negative.

Kotlin

val number = -5
val result = if (number >= 0) number else throw [1]("Negative number")

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

AExceptionHandler

Bprintln

Creturn

DIllegalArgumentException

Attempts:

3 left

💡 Hint

Common Mistakes

Using println instead of throwing an exception

Trying to return a value instead of throwing

Using a non-exception class

In Kotlin, you throw an exception using the 'throw' keyword followed by an exception class instance like IllegalArgumentException.

2fill in blank

medium

Complete the code to throw an exception as an expression inside a function.

Kotlin

fun getPositiveNumber(number: Int): Int = if (number > 0) number else throw [1]("Number must be positive")

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

AError

BRuntimeException

CException

Dprintln

Attempts:

3 left

💡 Hint

Common Mistakes

Using println instead of throw

Using Error which is for serious system errors

Using Exception which is a checked exception in Java but less common in Kotlin

Throwing RuntimeException is a common way to signal an error condition in Kotlin expressions.

3fill in blank

hard

Fix the error in the code by completing the throw expression correctly.

Kotlin

val value = 10
val result = if (value < 0) throw [1]("Negative value") else value

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

AIllegalStateException

Bthrow

Creturn

Dprint

Attempts:

3 left

💡 Hint

Common Mistakes

Using print instead of throw

Using return inside an expression

Trying to throw the throw keyword itself

You must throw an exception object like IllegalStateException, not use print or return in this context.

4fill in blank

hard

Fill both blanks to throw an exception with a custom message when the input is zero.

Kotlin

fun checkInput(input: Int): Int {
    return if (input != 0) input else throw [1]("Input cannot be zero: " + [2])
}

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

AIllegalArgumentException

Binput

Cnumber

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong variable name for the message

Throwing a generic RuntimeException without message

Not including the input value in the message

Throw IllegalArgumentException with the input value to show the error message clearly.

5fill in blank

hard

Fill all three blanks to throw an exception as an expression inside a map operation.

Kotlin

val numbers = listOf(1, 2, 0, 4)
val results = numbers.mapIndexed { [2], n ->
    if (n != 0) n else throw [1]("Zero found at index " + [2])
}.mapIndexed { [3], value -> value * 2 }

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

AIllegalStateException

Bn

Cindex

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names for index

Throwing generic exceptions without message

Confusing variable names in mapIndexed

Throw IllegalStateException with the index variable in the message, and use 'i' as the index variable in mapIndexed.