Thread: Magic square class (modular math problem)

Hi, I'm new to Java. I am trying to write a program that will print magic squares of odd order.

Here is the code:

class MagicSquare
{
     public static void main (String args[])
     {
          if(args.length > 1)
          {
               System.out.println("Too many arguments entered");
          }
          else
          {
               int sqrOrd = Integer.parseInt(args[0]);
               int magSqr[][] = new int [sqrOrd][sqrOrd];
               if (sqrOrd % 2 == 0)
               {
                    System.out.println("Square order is even");
               }
               else
               {
                    int rowNum;
                    int colNum;
 
                    for (rowNum = 0; rowNum < sqrOrd; rowNum++)
                    {
                         for (colNum = 0; colNum < sqrOrd; colNum++)
                         {
                              magSqr[rowNum][colNum] = -1;
                              //System.out.print(magSqr[rowNum][colNum]);
                         }
                         System.out.println();
                    }
 
                    int maxNum = sqrOrd * sqrOrd;
                    rowNum = 0;
                    colNum = sqrOrd / 2 + 1;
                    magSqr[rowNum][colNum] = 1;
 
                    for (int curNum = 1; curNum <= maxNum; curNum++)
                    {
                         if (magSqr[(rowNum - 1 + sqrOrd) % sqrOrd][(colNum + 1) % sqrOrd] == -1)
                         {
                              rowNum = (rowNum - 1 + sqrOrd) % sqrOrd;
                              colNum = (colNum - 1 + sqrOrd) % sqrOrd;
                         }
                         else
                         {
                              rowNum = (rowNum + 1) % sqrOrd;
                         }
                         magSqr[rowNum][colNum] = curNum;
                    }
                    for (rowNum = 0; rowNum < sqrOrd; rowNum++)
                    {
                         for (colNum = 0; colNum < sqrOrd; colNum++)
                         {
                              System.out.print(magSqr[rowNum][colNum] + "  ");
                         }
                         System.out.println();
                    }
               }
          }
     }       
}

My main problem is that, while the code compiles without any errors or warnings, the program does not print a magic square; it print an array where only some of the elements are replaced by the numbers 1 through n^2.

I think I am having some problem with the math controlling the if statements. Any help would be appreciated.

See Magic squares help - Java Forums