Flat an Int Array in Kotlin.

Flatten.kt

fun flatten(numbers: Array<Any>): ArrayList<Int> {
    val flattenReturn = arrayListOf<Int>()
    numbers.forEach { it ->
        if (it is Int) {
            flattenReturn.add(it)
        } else {
            val temp = flatten(it as Array<Any>)
            flattenReturn.addAll(temp)
        }
    }
    return flattenReturn;
}

/**
 * Test the method.
 */
fun main(args: Array<String>) {
    val first: Array<Any> = arrayOf(1, 2, arrayOf(3, 4))
    val flatThis : Array<Any> = arrayOf(first, 5, 6)

    val flatten = flatten(flatThis)

    println(flatten) // this prints [1, 2, 3, 4, 5, 6]
}