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 + y

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

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

fun 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

lambda { x: Int -> x + 1 }

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

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))

3, 4

Error

None

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

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

fun multiply { x: Int, y: Int }

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?

Return multiple values

Make a parameter optional

Declare a function as private

Accept variable numbers of arguments of the same type

None

How would you declare a function that returns a lambda?

fun myFunc(): (Int) -> String

fun myFunc() { Int -> String }

fun myFunc(): { Int -> String }

fun myFunc() -> lambda

None

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

(Int, String)

(Int) -> String

(String, Int) -> String

(String) -> Int

None

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

optional

vararg

default

inline

None

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

fun myFunc(lambda: Lambda)

fun myFunc(lambda: fun -> Unit)

fun myFunc(lambda: () -> Unit)

fun myFunc(lambda: function())

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 can have parameters and return values

Lambdas must have a return statement

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

They do not require parameters

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

fun myFunc: fun = return

fun myFunc(): () -> Unit

fun myFunc -> fun()

None

15.

What is a function in Kotlin?

A variable used to store data

An operator used in expressions

A method to define data types

A named block of code that performs a specific task

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

By using the execute keyword

By defining it inside a function

None

18.

What is a lambda expression in Kotlin?

A type of class

A private method inside a function

An error handling mechanism

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

None

19.

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

fun display(strings…: String)

fun display(strings: String*)

fun display(Strings: vararg)

fun display(vararg strings: String)

None

20.

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

optional

default

vararg

multivar

None

21.

What is the purpose of default parameters in Kotlin functions?

To specify the data type of a parameter

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

To make the function private

To declare multiple parameters with the same name

None

22.

How do you handle return values from a Kotlin function?

By storing the result in a variable using the assignment operator

By printing the result inside the function

Using the return keyword

By calling the function with an argument

None

23.

What is a local function in Kotlin?

A private function

A function that cannot return a value

A function declared inside another function

A function that can only be used in the main file

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) = x * y

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

None

25.

What is a single expression function in Kotlin?

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

A function that has no return type

A function that only accepts string parameters

A function that uses multiple lines of code

None

26.

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

call sayHello()

sayHello()

fun 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 data type, and arguments are the value

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

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

Parameters and arguments are exactly the same

None

Time’s up

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