In Kotlin, a class's behavior is defined by methods. Technically, a method is a member function, so, anything that we learn about functions in the following chapters also applies to the methods:

class Cupcake(val flavour: String) {
  fun eat(): String {
    return "nom, nom, nom... delicious $flavour cupcake"
  }
}

The eat() method returns a String value. Now, let's call the eat() method, as shown in the following code:

fun main(args: Array<String>) {
    val myBlueberryCupcake = Cupcake("Blueberry")
    println(myBlueberryCupcake.eat())
}

The following expression is the output of the preceding code:

Nothing mind-blowing, but this is our first method. Later on, we'll do more interesting stuff.