// Textbook fragment 03.07
  /** Insertion sort of an array of characters into non-decreasing order */
  public static void insertionSort(char[] a) {
    int n = a.length;
    for (int i = 1; i < n; i++) {       // index from the second character in a
      char cur = a[i];                  // the current character to be inserted
      int j = i - 1;                    // start comparing with cell left of i
      while ((j >= 0) && (a[j] > cur))  // while a[j] is out of order with cur
        a[j + 1] = a[j--];              // move a[j] right and decrement j
      a[j + 1]=cur;                     // this is the proper place for cur
    }
  }