AdditivePersistence.kt

package com.avighnash.exercises

object AdditivePersistence {
    fun calc(num: Long): Int {
        var x = num
        var i = 0

        while (x.toString().toCharArray().map(Character::getNumericValue).size != 1) {
            x = x.toString().toCharArray().map(Character::getNumericValue).sum().toLong()
            i++
        }
        return i
    }
}