Kotlin Functions and Lambdas Quiz

Welcome to the Kotlin Functions and Lambdas Quiz! This quiz will test your understanding of Kotlin’s functions and lambda expressions, essential tools for writing clean, efficient, and reusable code. You’ll explore key concepts such as function declarations, parameter handling, lambda expressions, higher-order functions, and more. Each question is crafted to reinforce your knowledge and provide valuable insights into best practices when working with functions and lambdas in Kotlin.

Which of the following is an example of a single-expression function?

fun add(x: Int, y: Int) = x + y

fun add = x + y

fun add(x: Int, y: Int): Int { return x + y }

add = { x: Int, y: Int -> x + y }

None

How can you execute a lambda directly without assigning it to a variable?

lambda { x: Int -> x + 1 }

{ x: Int -> x + 1 }(5)

lambda(x: Int) = x + 1

fun (x: Int) -> x + 1

None

What will be the output of the following code?

val multiply = { x: Int, y: Int -> x * y }; 
println(multiply(3, 4))

Error

3, 4

None

Which Kotlin code correctly shows a lambda being assigned to a variable?

fun multiply { x: Int, y: Int }

val multiply = (x, y) => x * y

val multiply = { x: Int, y: Int -> x * y }

lambda multiply = (x, y) -> x * y

None

What does the vararg keyword allow you to do in Kotlin?

Make a parameter optional

Declare a function as private

Return multiple values

Accept variable numbers of arguments of the same type

None

How would you declare a function that returns a lambda?

fun myFunc() -> lambda

fun myFunc(): (Int) -> String

fun myFunc(): { Int -> String }

fun myFunc() { Int -> String }

None

Which function type represents a function that accepts an Int and returns a String?

(String) -> Int

(Int, String)

(Int) -> String

(String, Int) -> String

None

Which keyword is used to specify that a Kotlin function parameter is optional?

optional

inline

vararg

default

None

How are functions declared to accept a lambda as a parameter?

fun myFunc(lambda: fun -> Unit)

fun myFunc(lambda: function())

fun myFunc(lambda: Lambda)

fun myFunc(lambda: () -> Unit)

None

10.

What happens when you place parentheses after a lambda expression?

It passes parameters to the lambda but does not execute it

It executes the lambda

It converts the lambda to a function

It defines the lambda

None

11.

Which statement about Kotlin lambda expressions is correct?

Lambdas cannot be assigned to variables

Lambdas can only be used in loops

Lambdas must have a return statement

Lambdas can have parameters and return values

None

12.

Which code snippet correctly demonstrates passing a function reference as an argument?

outputConversion(::myFunction, 10.0)

outputConversion(myFunction(), 10.0)

outputConversion(myFunction, 10.0)

outputConversion(myFunction::, 10.0)

None

13.

What is the main advantage of using higher-order functions in Kotlin?

They do not require parameters

They allow functions or lambdas to be passed as arguments or returned as results

They automatically handle exceptions

They run faster than regular functions

None

14.

How do you declare a function that returns a function as its result?

fun myFunc: fun = return

fun myFunc(): () -> Unit

fun myFunc -> fun()

fun myFunc() -> fun

None

15.

What is a function in Kotlin?

A method to define data types

A named block of code that performs a specific task

An operator used in expressions

A variable used to store data

None

16.

Which syntax assigns a function reference to a variable in Kotlin?

val myVar = ::myFunction

val myVar = myFunction

val myVar = myFunction()

val myVar = fun myFunction

None

17.

How can a lambda be directly executed in Kotlin?

By using the call keyword

By defining it inside a function

By using the execute keyword

By placing parentheses at the end of the expression with any required arguments

None

18.

What is a lambda expression in Kotlin?

A private method inside a function

A self-contained block of code that can be passed around as a variable

A type of class

An error handling mechanism

None

19.

Which of the following is the correct syntax for a function with a variable number of string parameters?

fun display(Strings: vararg)

fun display(vararg strings: String)

fun display(strings…: String)

fun display(strings: String*)

None

20.

What keyword is used to specify that a function can accept a variable number of parameters?

multivar

optional

default

vararg

None

21.

What is the purpose of default parameters in Kotlin functions?

To make the function private

To specify the data type of a parameter

To declare multiple parameters with the same name

To make a parameter optional and use a default value if no argument is passed

None

22.

How do you handle return values from a Kotlin function?

By storing the result in a variable using the assignment operator

Using the return keyword

By printing the result inside the function

By calling the function with an argument

None

23.

What is a local function in Kotlin?

A function that cannot return a value

A function that can only be used in the main file

A private function

A function declared inside another function

None

24.

Which of the following is a correct single-expression function that multiplies two numbers?

fun multiply x: Int y: Int -> x * y

fun multiply = (x, y) -> x * y

fun multiply(x: Int, y: Int): Int { return x * y }

fun multiply(x: Int, y: Int) = x * y

None

25.

What is a single expression function in Kotlin?

A function that only accepts string parameters

A function that contains a single expression and can be written in a more concise form

A function that uses multiple lines of code

A function that has no return type

None

26.

What is the syntax for calling a function named sayHello that takes no parameters and returns no value?

fun sayHello()

call sayHello()

sayHello{}

sayHello()

None

27.

Which keyword is used to declare a function in Kotlin?

fun

declare

def

func

None

28.

What is the difference between parameters and arguments in the context of functions?

Parameters are the values passed when calling a function, and arguments are defined inside the function

Parameters are defined in the function declaration, and arguments are the actual values passed when calling the function

Parameters are the data type, and arguments are the value

Parameters and arguments are exactly the same

None

Time’s up

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