Companion vs top-level functions decision in Kotlin - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a companion object function named greet.

Kotlin

class Greeter {
    companion object {
        fun [1]() = "Hello from companion"
    }
}

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

Agreet

Bhello

CsayHello

Dwelcome

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different function name than 'greet'.

The function name should be greet as specified.

2fill in blank

medium

Complete the code to define a top-level function named greet that returns a greeting string.

Kotlin

fun [1]() = "Hello from top-level function"

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

Agreet

BsayHello

Cwelcome

Dhello

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a function name that does not clearly indicate greeting.

The top-level function should be named greet to match the greeting purpose.

3fill in blank

hard

Fix the error in calling the companion object function greet from class Greeter.

Kotlin

fun main() {
    println(Greeter.[1]())
}

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

Ahello

BsayHello

Cwelcome

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong function name or forgetting to use the class name.

The companion object function is called using the class name followed by the function name greet.

4fill in blank

hard

Fill both blanks to create a companion object function that returns a greeting with a name parameter.

Kotlin

class Greeter {
    companion object {
        fun greet([1]: String): String = "Hello, [2]"
    }
}

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

Aname

Bperson

Cuser

Dguest

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the parameter and the string interpolation.

The parameter name must be the same in the function signature and the string interpolation to work correctly.

5fill in blank

hard

Fill all three blanks to create a top-level function that returns a greeting with a name parameter.

Kotlin

fun [1]([2]: String): String = "Hello, $[3]"

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

AsayHello

Bname

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatch between parameter name and interpolation variable.

The function name is greet, the parameter is name, and the string interpolation uses name.