code: protected String[] add_string(String[] arr, String new_string) {
      String[] new_arr = new String[arr.length + 1];
      for (int ii = 0; ii < arr.length; ii++) {
        new_arr[ii] = arr[ii];
      }
      new_arr[arr.length] = new_string;
      return new_arr;
    }
docs: Returns a String array with new_string added to the end of arr.
  
  @param arr original string array
  @param new_string string to be added
  @return the new string array