Kotlin Kotlin Functions and Lambdas 2

Question 1

What is the type of a lambda that takes an Int and returns a String in Kotlin?

Accepted Answer

(Int) -> String

Answer

Kotlin function types use the `(ParameterTypes) -> ReturnType` syntax, so an Int-to-String lambda is `(Int) -> String`.

Question 2

What does the `crossinline` modifier do on a lambda parameter?

Accepted Answer

Prevents non-local returns inside the lambda

Answer

`crossinline` prevents non-local returns inside a lambda that is called from a different execution context while still allowing inlining.

Question 3

How do you reference an existing function as a value in Kotlin?

Accepted Answer

Using the `::` operator

Answer

The `::` operator creates a function reference, allowing an existing function to be treated as a first-class value.

Question 4

Which built-in higher-order function applies a transformation to each element of a collection?

Accepted Answer

map

Answer

`map` applies a given transformation function to each element of a collection and returns a new list of results.

Question 5

What does `noinline` do on an inline function parameter?

Accepted Answer

Prevents that specific lambda parameter from being inlined

Answer

`noinline` disables inlining for a specific lambda parameter of an `inline` function, useful when you need to store or return the lambda.

Kotlin Practice Test