public void selectionSort(int[] arr){
    for (int i = 0; i < arr.length - 1; i++) {
        int index = i;
        for (int j = i + 1; j < arr.length; j++) {
            if (arr[j] < arr[index]) {
                index = j;
            }
        }
        swap(arr[index], arr[i]);
    }
}

private void swap(int num1, int num2) {
    int temp = num1;
    num1 = num2;
    num2 = temp;
}