Parameters with default values in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a parameter with a default value in Kotlin?

A parameter with a default value is a function parameter that has a preset value. If the caller does not provide an argument for it, the default value is used automatically.

beginner

How do you define a default value for a parameter in Kotlin?

You assign a value to the parameter in the function declaration using the equals sign, like fun greet(name: String = "Guest").

beginner

What happens if you call a Kotlin function without providing an argument for a parameter that has a default value?

The function uses the default value specified for that parameter instead of requiring an argument.

intermediate

Can you mix parameters with and without default values in Kotlin functions?

Yes, you can mix them. Parameters with default values can be placed after or before parameters without default values, but when calling the function, you must provide arguments for parameters without defaults.

beginner

Why are default parameter values useful in Kotlin?

They simplify function calls by reducing the number of arguments needed, avoid overloads, and make code easier to read and maintain.

How do you specify a default value for a parameter in Kotlin?

A By assigning a value in the function declaration, e.g., fun f(x: Int = 5)

B By setting the value inside the function body

C By using the keyword default before the parameter

D By declaring the parameter as nullable

In Kotlin, default values are assigned directly in the function parameter list using the equals sign.

What happens if you call a Kotlin function without an argument for a parameter that has a default value?

A The default value is used

B The program throws an error

C The parameter is set to null

D You must always provide all arguments

Kotlin uses the default value automatically if no argument is provided.

Can you omit arguments for parameters without default values when calling a Kotlin function?

A Only if the function is inline

B Yes, Kotlin fills them with zero

C Yes, Kotlin fills them with null

D No, you must provide arguments for all parameters without defaults

Parameters without default values require arguments when calling the function.

How can you call a Kotlin function and specify only some arguments when others have default values?

A By calling the function multiple times

B By using named arguments to specify which parameters you want to set

C By passing null for the missing arguments

D By using varargs

Named arguments let you specify only some parameters and rely on defaults for others.

Which of the following is a benefit of using default parameter values in Kotlin?

A Prevents null pointer exceptions

B Makes functions run faster

C Reduces the need for multiple overloaded functions

D Automatically documents the function

Default values reduce the need to write many overloaded versions of the same function.

Explain how default parameter values work in Kotlin and why they are useful.

Think about how you can make function calls simpler by not always giving every argument.

Describe how you can call a Kotlin function that has some parameters with default values and some without.

Consider how named arguments help when mixing parameters.