JuniorTheoryCommon

What does the program print?

KOTLIN

interface Greeter {
    fun name(): String
    fun greet() = "Hi, ${name()}"
}
class Bot : Greeter {
    override fun name() = "Bot"
}

fun main() {
    val g: Greeter = Bot()
    println(g.greet())
}

Hi, Bot

Expecting a compile error: thinking a class must override every method of its interface. Only methods without a body must be overridden; greet() comes ready-made.
Expecting Hi, name(): thinking a call inside a string is printed as text. In a string template, ${name()} runs the call and inserts what it returns.

What does the program print if Bot also overrides greet() to return "Beep"?
Can one class implement two interfaces at once?

Back to questions Open topic in roadmap →Answer it yourself — Quiz

Back to questions

JuniorTheoryCommon

What does the program print?

KOTLIN

interface Greeter {
    fun name(): String
    fun greet() = "Hi, ${name()}"
}
class Bot : Greeter {
    override fun name() = "Bot"
}

fun main() {
    val g: Greeter = Bot()
    println(g.greet())
}

Hi, Bot

Expecting a compile error: thinking a class must override every method of its interface. Only methods without a body must be overridden; greet() comes ready-made.
Expecting Hi, name(): thinking a call inside a string is printed as text. In a string template, ${name()} runs the call and inserts what it returns.

What does the program print if Bot also overrides greet() to return "Beep"?
Can one class implement two interfaces at once?

Back to questions Open topic in roadmap →Answer it yourself — Quiz