public abstract class MagicSquare

{

    private int startValue;

    private int n;

    private Integer[][] cells;


    public MagicSquare(int startValue, int n) throws IllegalArgumentException
    {
        if (n < 3)
            throw new IllegalArgumentException();

        this.n = n;
        this.startValue = startValue;
        cells = new Integer[n][n];


    }


    public int getStartValue()

    {

        return startValue;

    }


    public int getOrder()

    {

        return n;

    }


    public boolean isCellFilled(int row, int col)
    {

        return (cells[row][col] != null);
    }


    public boolean isCellFilled(int index)
    {

        return isCellFilled(index/n, index%n);
    }


    public int getCell(int row, int col)
    {

        return cells[row][col].intValue();
    }


    public int getCell(int index)

    {

        return getCell(index/n, index%n);
    }


    public int getComplementaryCell(int row, int col)
    {

        return getCell(n-row, n-col);

    }


    public int getComplementaryCell(int index)
    {

        return getComplementaryCell(index/n, index%n);
    }


    public void setCell(int row, int col, int value)
    {

        cells[row][col] = new Integer(value);
    }


    public void setCell(int index, int value)
    {

        setCell(index/n, index%n, value);
    }


    public String toString()

    {

        StringBuffer sb = new StringBuffer();

        for (int row=0; row<n; row++)
        {
            for (int col=0; col<n; col++)
            {
                sb.append(getCell(row, col));
                sb.append(" ");
            }
            sb.setCharAt(sb.length()-1, '\n');
        }
        return sb.toString();


    }

}