Mine

Board board; for (int row = 0; row < board.height; ++row){  if (!std::getline(is, line) || line.size() != 20)    return;  for (int col = 0; col < board.width; ++col)  {    I2 ix(col, row);    char ch = line[col];    if (ch == '#')      board.setKind(ix, Board::Wall);    if (ch == '.')      board.setKind(ix, Board::Air);  }}