Pass an integer by reference in Kotlin

This article explores different ways to pass an integer by reference in Kotlin.

1. Using a Wrapper class

The idea is to create a reference class that contains the integer as a member field. This function is demonstrated below:

data class IntHolder(var value: Int) {

override fun toString(): String {

return value.toString()

}

fun increment(i: IntHolder) {

i.value += 1

}

fun main() {

val i = IntHolder(1)

println(i) // 1

increment(i)

println(i) // 2

}

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2. Using an Array

We can also use an array of length one to wrap an integer.

fun increment(arr: Array<Int>) {

arr[0]++

}

fun main() {

var i = 1

println(i) // 1

val arr = arrayOf(i)

increment(arr)

i = arr[0]

println(i) // 2

}

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3. Using AtomicInteger

Alternately, you can use the AtomicInteger class, which offers several useful functions for manipulating an integer.

import java.util.concurrent.atomic.AtomicInteger

fun set(i: AtomicInteger) {

i.incrementAndGet()

}

fun main() {

val i = AtomicInteger(1)

println(i) // 1

set(i)

println(i) // 2

}

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That’s all about passing an integer by reference in Kotlin.

Pass an integer by reference in Kotlin

1. Using a Wrapper class

2. Using an Array

3. Using AtomicInteger

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