class InsertionSort {

    static void insertionSort(int a[]) {
        for (int i = 1; i < a.length; i++) {
            int index = i;
            while (index > 0 && a[i] < a[index - 1]) {
                int temp = a[index];
                a[index] = a[index - 1];
                a[index - 1] = temp;
                index--;
            }
        }
    }

    static void insertionSort2(int a[]) {
        for (int i = 1; i < a.length; i++) {
            int current = a[i];
            int index = i;
            while (index > 0 && current < a[index - 1]) { // musi być tutaj current zamiast a[i]. Dlaczego?
                int temp = a[index];
                a[index] = a[index - 1];
                a[index - 1] = temp;
                index--;
            }
        }
    }

    public static void main(String[] args) {

        int[] a = {9991,2,7,6,3,2,-231,4542,24,0,21};
        insertionSort(a);
        System.out.println(Arrays.toString(a)); // [2, 7, 6, 3, 2, -231, 4542, 24, 0, 21, 9991]

        insertionSort2(a);
        System.out.println(Arrays.toString(a)); // [-231, 0, 2, 2, 3, 6, 7, 21, 24, 4542, 9991]

    }
}