1. 利用指针遍历二维数组：

  int ary[3][3] = {{11, 12, 13},
                   {21, 22, 23},
                   {31, 32, 33}};
  for (int i=0; i<3; ++i) {
    for (int j=0; j<3; ++j) {
      std::cout << std::setw(3) << *(*(ary + i) + j);
    }
    std::cout << std::endl;
  }