Fix the MagicSquare program so that it compiles and works correctly, according t

Question

Fix the MagicSquare program so that it compiles and works correctly, according to the comments at
the top of the file.

// MagicSquare.java -- This class generates magic squares (a magic square is a
// two-dimensional matrix/array of integers where every
// integer from 1 through (n*n) appears once, and every row,
// column, and diagonal has the same sum).
//
// To generate an NxN magic square for an odd value of N, we
// use the following algorithm: place 1 in the center of the top
// row. For each consecutive value, we move one square up and to
// the left, wrapping around the top/left of the matrix as needed.
// If the next square is already occupied, we move one square down
// from the last square we filled instead, and then resume our "up
// and to the left" movement.
//


import java.util.*;

// FIX THIS CLASS

public class MagicSquare
{
public static int [] generateSquare (int size)
{
int [][] square = new int[size*size]; int value, row, col,
nextRow; nextCol;

// Initialize the square to all 0's
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++)
square[j][j] = -1;
} }

/* Square-filling code. We begin in the center of the
// top row, and move up and to the left for each
// succeeding value /

row = 0;
col = size/2;
value = 1;

while (
value < (
size * size
)
)
{
// Place the current value...
square[row
][
col] =
value;

// ...and move to the next cell
nextRow =
row
-
1;
nextCol = col;

// If we run off the edge, reset the value of nextRow/Col
if (nextRow < 0);
nextRow == size - 1;

if (nextCol <= 0)
nextCol = size -1;

row = nextCol;
col = nextRow;
}*/

return square;
}

public static void main (String [] args)
{
Scanner sc = new Scanner(System.in);

System.out.print("Please enter an odd positive integer: ");
int n = sc.nextInt();

if (n <= 0)
{
System.out.println("Error: must enter a positive integer!");
}
else if (n % 2 == 0)
{
System.out.println("Error: must enter an odd integer!");
}
else
{
int [][] s = generateSquare(n);
int sum = 0;

System.out.println("Your magic square is: ");

for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
System.out.print(s[i][j] + " ");
}

sum += s[i][0];

System.out.println();
}

System.out.println();
System.out.println("Row/column/diagonal sum: " + sum);
}
}
}

Explanation / Answer

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//MagicSquare.java -- This class generates magic squares (a magic square is a
//two-dimensional matrix/array of integers where every
//integer from 1 through (n*n) appears once, and every row,
//column, and diagonal has the same sum).
//
//To generate an NxN magic square for an odd value of N, we
//use the following algorithm: place 1 in the center of the top
//row. For each consecutive value, we move one square up and to
//the left, wrapping around the top/left of the matrix as needed.
//If the next square is already occupied, we move one square down
//from the last square we filled instead, and then resume our "up
//and to the left" movement.
//

import java.util.*;


public class MagicSquare {
    public static int[][] generateSquare(int size) throws Exception{
        int[][] square = new int[size][size];
        int value, row, col, nextCol, nextRow;

        // Initialize the square to all 0's
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++)
                square[i][j] = 0;
        }
       
        row = 0; col = size/2; value = 1;
        nextRow = row; nextCol = col;
       
        while(value <= size*size ){           
           
            if(nextRow <= -1){
                nextRow = size-1;
            }else
            if(nextRow > size-1){
                nextRow = 0;
            }
            if(nextCol <= -1){
                nextCol = size - 1;
            }else
            if(nextCol > size-1){
                nextCol = 0;
            }
           
            if(square[nextRow][nextCol]==0){
                row = nextRow;
                col = nextCol;
                square[row][col] = value;
            }else{
                nextRow = row + 1;
                nextCol = col;
                continue;
            }
            nextRow = row - 1;
            nextCol = col + 1;
                                   
            value++;
        }
       
       
        return square;
    }


    public static void main(String[] args) throws Exception{
        Scanner sc = new Scanner(System.in);

        System.out.print("Please enter an odd positive integer: ");
        int n = sc.nextInt();

        if (n <= 0) {
            System.out.println("Error: must enter a positive integer!");
        } else if (n % 2 == 0) {
            System.out.println("Error: must enter an odd integer!");
        } else {
            int[][] s = generateSquare(n);
            int sum = 0;

            System.out.println("Your magic square is: ");

            for (int i = 0; i < n; i++) {
                for (int j = 0; j < n; j++) {
                    System.out.print(s[i][j] + " ");
                }

                sum += s[i][0];

                System.out.println();
            }

            System.out.println();
            System.out.println("Row/column/diagonal sum: " + sum);
        }
    }
}

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