JuniorTheoryCommon

What does the program print?

KOTLIN

class Counter {
    var count = 0
    val stored = count * 10
    val computed get() = count * 10
}

fun main() {
    val c = Counter()
    c.count = 2
    println("${c.stored} ${c.computed}")
}

0 20

Expecting 20 20: thinking stored changes when count does. Its initializer runs once, when the object is created, so stored keeps 0.
Expecting 0 0: thinking a property with get() is computed once like any other. get() runs on every read, so it sees count = 2.

What does c.computed show after c.count = 5, and why?
Which of the two properties keeps its value inside the object, and which does not?

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JuniorTheoryCommon

What does the program print?

KOTLIN

class Counter {
    var count = 0
    val stored = count * 10
    val computed get() = count * 10
}

fun main() {
    val c = Counter()
    c.count = 2
    println("${c.stored} ${c.computed}")
}

0 20

Expecting 20 20: thinking stored changes when count does. Its initializer runs once, when the object is created, so stored keeps 0.
Expecting 0 0: thinking a property with get() is computed once like any other. get() runs on every read, so it sees count = 2.

What does c.computed show after c.count = 5, and why?
Which of the two properties keeps its value inside the object, and which does not?

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