Selection Sort in Kotlin

SelectionSort.kt

/**
 * Complexity O(n^2)
 */

/**
 * Unsorted Data Source
 */
var unsortedArray: ArrayList<Int> = arrayListOf(45,7,3,6,12,657,568,23412,3,46,647,234,7687,686,235,564,768568,345,23,1,23,3,46,7,8,945,34)


fun main() {
   //print out the sorted array returned from function  
   System.out.print(selectionSort(unsortedArray))
}

//gets input of unsorted Array and returns sorted Array
fun selectionSort(array: ArrayList<Int>): ArrayList<Int>{
    //Selection sort uses 2 Integers, For saving the lowest value found in each iteration, and its index
    var lowerValue: Int = 0
    var lowerValueIndex: Int = 0
    
    //if array is empty simpley return the array
    if(array.isEmpty()){
        return array
    }else{
        //loop through the array until last index, first loop will iterate the counter for each element 
        array.forEachIndexed{indexA, _ -> 
        //each element on every index will be considered as lowest and then be compared with each element until finds least element
        lowerValue = array[indexA]
          
        //loop entire array starting from [sorted arraya] + 1 until end until least value is found
        for(indexB in indexA until array.size){
            if(lowerValue > array[indexB]){
                lowerValue = array[indexB]
                lowerValueIndex = indexB
            }
        }
        //swap values, from array 
        swap(array, indexA, lowerValueIndex, lowerValue)
        }
        //after sorting return the array
        return array
    }
}

fun swap(array: ArrayList<Int>, indexA: Int, indexB: Int, lowerVal: Int){
        var tempValue = array[indexA]
        array[indexA] = lowerVal
        array[indexB] = tempValue
}