int[] a9 = {19, 7, 99, 18};
        swap(a9, 0, 2);
        printArray ("a9: ", a9);
        System.out.println("");
        System.out.println("15.");
        int[] a10 = { 99, 7, 29, 18};
        System.out.println("Largest from start:" + indexOfLargestElement(a10, 0));
        System.out.println("Largest from pos 1:" + indexOfLargestElement(a10, 1));
        System.out.println("");
        System.out.println("16.");
        int[] rnd = randomArray(25, 100, 999);
        printArray("Quelle", rnd);
        reverseSort(rnd);
        printArray("Sortiert", rnd);




public static void swap (int[] a, int i, int j) {
        int ai = a[i];
        int aj = a[j];
        a[i] = aj;
        a[j] = ai;
    }

    public static int indexOfLargestElement (int[] a, int startPos) {
        int i = 0;
        int p = 0;
        for (; startPos < a.length; startPos++) {
            if (a[startPos] > i) {
                i = a[startPos];
                p = startPos;
            }
        }
        return p;
    }

    public static void reverseSort (int[] a) {
        for (int i = 0; i < a.length; i++) {
            int max = indexOfLargestElement(a, i);
            swap(a, i, max);
        }
    }