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Thread: Magic Squares, input confusion

  1. #1
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    Default Magic Squares, input confusion

    Hello, I'm running into a problem with my fourth homework assignment for CS201. Yes, my question involves homework, but I'm not asking for code.

    I can't figure out how to read the magicData file. I'm using Eclipse, and while I believe it should be in the project's main directory, I've also placed copies in the src and bin folders. So, I don't believe the error is a result of the file being misplaced or incorrectly named (the file has no extension).

    Here's my driver program:
    // ****************************************************************
    // SquareTest.java
    //
    // Uses the Square class to read in square data and tell if
    // each square is magic.
    //
    // ****************************************************************
     
    import java.util.Scanner;
    import java.io.IOException;
    import java.io.File;
     
    public class SquareTest {
    	public static void main(String[] args) throws IOException {
    		Scanner scan = new Scanner(new File("magicData"));
    		// make sure that the file magicData is in the current directory
     
    		int count = 1; // count which square we're on
    		int size = scan.nextInt(); // size of next square
     
    		// Expecting -1 at bottom of input file
    		while (size != -1) {
     
    			// create a new Square of the given size
    			Square s = new Square(size);
     
    			// call its read method to read the values of the square
    			System.out.println("\n***** Square " + count + " *****");
     
    			// print the square
    			s.printSquare();
     
    			// print the sums of its rows
    			for (int row = 0; row < size; row++) {
    				System.out
    				.println("Sum of row " + row + "is: " + s.sumRow(row));
    			}
    			System.out.println();
     
    			// print the sums of its columns
    			for (int col = 0; col < size; col++) {
    				System.out.println("Sum of columns " + col + " is: "
    						+ s.sumCol(col));
    			}
    			System.out.println();
     
    			// print the sum of the main diagonal
    			System.out.println("The sum of the main diagonal is: "
    					+ s.sumMainDiag());
    			System.out.println();
     
    			// print the sum of the other diagonal
    			System.out.println("The sum of the other diagonal is: "
    					+ s.sumOtherDiag());
    			System.out.println();
     
    			// determine and print whether it is a magic square
    			System.out.println("Is it a magic square: " + s.magic());
     
    			// get size of next square
    			size = scan.nextInt();
    			count++;
    		}
    	}
    }

    Here's my class file:
    // ****************************************************************
    // Square.java
    //
    // Define a Square class with methods to create and read in
    // info for a square matrix and to compute the sum of a row,
    // a col, either diagonal, and whether it is magic.
    //
    // ****************************************************************
     
    import java.util.Scanner;
     
    public class Square {
    	int[][] square;
     
    	// --------------------------------------
    	// create new square of given size
    	// --------------------------------------
    	public Square(int size) {
    		square = new int[size][size]; // table user defined
    	}
     
    	// --------------------------------------
    	// return the sum of the values in the given row
    	// --------------------------------------
    	public int sumRow(int row) {
    		int sum = 0;
    		for (int col = 0; col < square.length; col++) {
    			sum = sum + square[row][col];
    		}
    		return sum;
    	}
     
    	// --------------------------------------
    	// return the sum of the values in the given column
    	// --------------------------------------
    	public int sumCol(int col) {
    		int sum = 0;
    		for (int row = 0; row < square.length; row++) {
    			sum = sum + square[row][col];
    		}
    		return sum;
    	}
     
    	// --------------------------------------
    	// return the sum of the values in the main diagonal
    	// --------------------------------------
    	public int sumMainDiag() {
    		int sum = 0;
    		for (int j = 0; j < square.length; j++) {
    			sum = sum + square[j][j];
    		}
    		return sum;
    	}
     
    	// --------------------------------------
    	// return the sum of the values in the other ("reverse") diagonal
    	// --------------------------------------
    	public int sumOtherDiag() {
    		int sum = 0;
    		for (int j = 0; j < square.length; j++) {
    			sum = sum + square[j][square.length - 1 - j];
    		}
    		return sum;
    	}
     
    	// --------------------------------------
    	// return true if the square is magic (all rows, cols, and diags
    	// have same sum), false otherwise
    	// --------------------------------------
    	public boolean magic() {
    		boolean answer = true;
    		int sum = sumMainDiag();
    		if (sumOtherDiag() != sum) {
    			answer = false;
    		} else {
    			for (int row = 0; row < square.length; row++) {
    				if (sum != sumRow(row)) {
    					answer = false;
    				}
    			}
    			for (int col = 0; col < square.length; col++) {
    				if (sum != sumCol(col)) {
    					answer = false;
    				}
    			}
    		}
    		return answer;
    	}
     
    	// --------------------------------------
    	// read info into the square from the input stream associated with
    	// the Scanner parameter
    	// --------------------------------------
    	public void readSquare(Scanner scan) {
    		for (int row = 0; row < square.length; row++)
    			for (int col = 0; col < square.length; col++)
    				square[row][col] = scan.nextInt();
    	}
     
    	// --------------------------------------
    	// print the contents of the square, neatly formatted
    	// --------------------------------------
    	public void printSquare() {
    		for (int row = 0; row < square.length; row++)
    			for (int col = 0; col < square.length; col++) {
    				System.out.print(square[row][col] + " ");
    				System.out.println();
    			}
    	}
     
    }

    And here's the magicData file.
    3
    8  1  6
    3  5  7
    4  9  2
    7
    30  39  48   1  10  19  28
    38  47   7   9  18  27  29
    46   6   8  17  26  35  37
    5   14  16  25  34  36  45
    13  15  24  33  42  44   4
    21  23  32  41  43   3  12
    22  31  40  49   2  11  20
    4
    48   9   6   39
    27  18  21   36
    15  30  33   24
    12  45  42    3
    3
    6  2  7
    1  5  3
    2  9  4
    4
    3  16   2  13
    6   9   7  12
    10  5  11   8
    15  4  14   1
    5
    17  24  15   8   1
    23   5  16  14   7
     4   6  22  13  20
    10  12   3  21  19
    11  18   9   2  25
    7
    30  39  48   1  10  28  19
    38  47   7   9  18  29  27
    46   6   8  17  26  37  35
    5   14  16  25  34  45  36
    13  15  24  33  42   4  44
    21  23  32  41  43  12   3
    22  31  40  49   2  20  11
    -1

    Also, here's the frustrating output I'm currently receiving:
    0 
    0 
    0 
    0 
    0 
    etc...
     
    Sum of row 0is: 0
    Sum of row 1is: 0
    Sum of row 2is: 0
    Sum of row 3is: 0
    Sum of row 4is: 0
    Sum of row 5is: 0
    Sum of row 6is: 0
    Sum of row 7is: 0
    Sum of row 8is: 0
    Sum of row 9is: 0
    Sum of row 10is: 0
    Sum of row 11is: 0
    Sum of row 12is: 0
    Sum of row 13is: 0
    Sum of row 14is: 0
    Sum of row 15is: 0
    Sum of row 16is: 0
    Sum of row 17is: 0
    Sum of row 18is: 0
    Sum of row 19is: 0
    Sum of row 20is: 0
    Sum of row 21is: 0
    Sum of row 22is: 0
    Sum of row 23is: 0
     
    Sum of columns 0 is: 0
    Sum of columns 1 is: 0
    Sum of columns 2 is: 0
    Sum of columns 3 is: 0
    Sum of columns 4 is: 0
    Sum of columns 5 is: 0
    Sum of columns 6 is: 0
    Sum of columns 7 is: 0
    Sum of columns 8 is: 0
    Sum of columns 9 is: 0
    Sum of columns 10 is: 0
    Sum of columns 11 is: 0
    Sum of columns 12 is: 0
    Sum of columns 13 is: 0
    Sum of columns 14 is: 0
    Sum of columns 15 is: 0
    Sum of columns 16 is: 0
    Sum of columns 17 is: 0
    Sum of columns 18 is: 0
    Sum of columns 19 is: 0
    Sum of columns 20 is: 0
    Sum of columns 21 is: 0
    Sum of columns 22 is: 0
    Sum of columns 23 is: 0
     
    The sum of the main diagonal is: 0
     
    The sum of the other diagonal is: 0
     
    Is it a magic square: true
     
    etc...

    Any ideas as to why my program currently disregards the contents of magicData?


  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: Magic Squares, input confusion

    hmm.. so far as I can tell no where in your code are you populating the Square object with the input values. I also don't see any code that's reading in the data from the files, only the size.

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