Question

I’m doing a magicsquare program that allows a user to input numbers >0 to form a magicsquare. What a magic square is, is pretty much a square, meaning that n has to have n(squared) numbers. Much like ticTacToe, all the rows, columns, and diagonals each have the same sum to be considered a magic square When I run my program, It always confuses the 2D array set and claim that the set of numbers are a magicsquare when usually, it isnt necessarily so. Please help!

import java.util.Scanner;

public class SquareRunner
{
 public static void main(String[] args)
 {
     Scanner in = new Scanner(System.in);
     Square test = new Square();
     System.out.println("Enter a row of integers. When you are finished, type 'n' in a new line");
     boolean flag = false;
     while(!flag)
     {
        String numbers = in.next();
        if(numbers.equals("n"))
        flag = true;
        else
        test.add(numbers);
     }
     test.isMagic();

 }
}

public class Square
{
  private int[][] values;
  private int row;

public Square()
{
    row = 0;
}

public void add(String numbers)
{
  int b = 1;
  int amount = numbers.length();
  values = new int[amount][amount];

  for(int j =0;j<amount;j++)
  {
      String a = numbers.substring(j,b);
      int convert = Integer.parseInt(a);
      values[row][j] = convert;

      b++;
   }
    row++;

}


public Boolean isMagic()
{
    int checkAmountColumns = values[0].length;
    int checkAmountRows = values.length;
    int isSquare = checkAmountColumns * checkAmountRows;

        for(int q = 0;q<values.length;q++)
        {
            for(int w=0;w<values[0].length;w++)
            {
                int checkZero = values[q][w];
                if(checkZero == 0)
                {
                    System.out.print("To be a perfect square, your number of rows and columns, n must be a perfect ");
                    System.out.println("Square i.e. 9 total numbers is 3 numbers per row");
                    return false;
                }
            }
        }
    if(checkAmountColumns != checkAmountRows || Math.sqrt(isSquare) != checkAmountColumns)
    {
        System.out.print("To be a perfect square, your number of rows and columns, n must be a perfect ");
        System.out.println("Square i.e. 9 total numbers is 3 numbers per row");
        return false;
    }

  else
    {
        int magicNumber = 0;
        int counter = 0;
        int compareTo = 0;

       //row to row
        for(int i =0;i<values.length;i++)
        {
            for(int j = 0;j<values[0].length;j++)
            {

                values[i][j] += compareTo;
                if(counter == 0)
                values[i][j] += magicNumber;

            }
            counter ++;
            compareTo = 0;
            if(compareTo != magicNumber)
            {
                System.out.println("This Selection of numbers is not a perfect square");
                return false;
            }
        }

        //column to column
        for(int i =0;i<values[0].length;i++)
        {
             for(int j = 0;j<values.length;j++)
             {

                  values[j][i] += compareTo;
                  if(counter == 0)
                  values[j][i] += magicNumber;

              }
              counter ++;
              compareTo = 0;
              if(compareTo != magicNumber)
              {
                System.out.println("This Selection of numbers is not a perfect square");
                return false;
              }

        }
        System.out.println("This selection of numbers is a MagicSquare!");
        return true;

    }
}
}

Answer 1

The first thing I notice is that your add() method probably won’t work correctly. Every time you call it, you overwrite the previous values member with a newly allocated array. This throws away the previous row that you entered.