code: public static void main(String[] args) throws IOException {
      if (args.length == 0) {
        System.out.println("Include a puzzle on the command line.");
      }
      for(int i=0; i < args.length; ++i) {
        Sudoku problem = new Sudoku(new FileInputStream(args[i]));
        System.out.println("Solving " + args[i]);
        problem.solve();
      }
    }
docs: Solves a set of sudoku puzzles.
  @param args a list of puzzle filenames to solve