Enum (Enumerated Types) Basics

In this lesson you will learn the basics of enums in Kotlin, so a fixed set of options can be referred to by readable names. This is for anyone searching for "Kotlin enum class how to use".

enum class creates an enumerated type representing a fixed set of options. Use it when you want to limit the possible values in advance, the way a traffic light only has red, green, and amber.

The sample code defines three options with enum class Color { RED, GREEN, BLUE } and assigns one of them to a variable as Color.RED. Notice how Color.values() lists every value in the enum.

A common stumbling block for beginners is not knowing that an enum class can carry properties and methods. A Kotlin enum is not just a list of constants - it can behave like an ordinary class, which makes it a powerful feature.

In real-world development enum classes are common wherever you handle a fixed set of options, such as order statuses or days of the week, and they make the code far more readable.

📖 Reference code

enum class Color { RED, GREEN, BLUE }

fun main() {
    val c = Color.RED
    println(c)
    println(Color.values().joinToString(", "))
}

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run Kotlin directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).