Enum with properties and methods in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an enum class in Kotlin?

An enum class in Kotlin is a special class that represents a group of constants. Each constant is an object of the enum type.

intermediate

How can you add properties to enum constants in Kotlin?

You add properties by defining a constructor in the enum class and passing values to each enum constant.

intermediate

Can enum classes in Kotlin have methods? How?

Yes, enum classes can have methods just like regular classes. You define them inside the enum class body.

beginner

Example: What does this enum represent?
<pre>enum class Direction(val degrees: Int) {
    NORTH(0), EAST(90), SOUTH(180), WEST(270)
}</pre>

This enum represents directions with their corresponding degrees on a compass.

advanced

How do you override a method for each enum constant individually?

You can override methods by defining them in the enum class and then providing a specific implementation for each constant using an anonymous class syntax.

How do you define a property for each enum constant in Kotlin?

A By declaring variables outside the enum class

B By adding a constructor with parameters to the enum class

C By using global variables

D By creating a separate class

Properties for enum constants are defined by adding a constructor with parameters to the enum class and passing values to each constant.

Can enum classes in Kotlin have functions?

A No, enums cannot have functions

B Yes, but only static functions

C Yes, enum classes can have functions like regular classes

D Only if the enum has no properties

Enum classes in Kotlin can have functions just like regular classes.

What keyword is used to define an enum class in Kotlin?

A enum class

B class

C enum

D object

The keyword 'enum class' is used to define an enum class in Kotlin.

How do you override a method for a specific enum constant?

A By defining the method outside the enum class

B By using inheritance

C By creating a new enum class

D By providing an anonymous class implementation for that constant

You override a method for a specific enum constant by providing an anonymous class implementation for that constant.

What will this code print?

enum class Color(val rgb: Int) {
    RED(0xFF0000), GREEN(0x00FF00), BLUE(0x0000FF)
}

fun main() {
    println(Color.GREEN.rgb)
}

A 65280

B Error

C Green

D 0x00FF00

The rgb property is an integer. 0x00FF00 in decimal is 65280, so it prints 65280.

Explain how to add properties and methods to an enum class in Kotlin with an example.

Think about how you pass values to enum constants and how you write functions inside the enum.

Describe how to override a method for individual enum constants in Kotlin.

Remember each constant can have its own implementation block.