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Thread: Summing a 4X4 Matrix in JOptionPane

  1. #1
    Member Java Neil's Avatar
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    Default Summing a 4X4 Matrix in JOptionPane

    Hi all...I'm a little stuck here. I have an assignment (summing all the numbers in a matrix) that I have figured out using the scanner and I need to figure out a way to turn it into a JOptionPane that "Echos the inputs as a[0] = xx, a[1] = xx, a[3] = xx, a[4] = xx, then displays the reslutl"

    This is what I have figured out so far. Please check my logic as well as I'm very new to two-dimensional arrays.

       import java.util.Scanner;
       public class sumMatrix {
          public static void main(String[] args) {
             Scanner input = new Scanner(System.in);
     
             System.out.print("Enter a 4 by 4 matrix row by row:");
             int[][] matrix = new int[4][4];
     
             for (int i = 0; i < matrix.length; i++)
                for (int j = 0; j < matrix[i].length; j++)
                   matrix[i][j] = input.nextInt();
     
             System.out.print("Sum of the Matrix is "	+ sumMatrix(matrix));
             double sum = sumMatrix(matrix);
          }
          public static double sumMatrix(int[][] m) {
             int sum = 0;
     
             for (int i = 0; i < m.length; i++)
                for (int j = 0; j < m[i].length; j++)
                   sum = sum + m[i][j];
     
             return sum;
          }  
       }

    Thanks once again for everyone's help. Thanks to you guys, I'm doing alright in this class.


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    Default Re: Summing a 4X4 Matrix in JOptionPane

    double sum = sumMatrix(matrix);

    Not sure what that's for.

    Anyway, you might be looking for something like:

    import javax.swing.JOptionPane;
     public class sumMatrix {
          public static void main(String[] args) {
     
     
             JOptionPane.showMessageDialog(null, "Enter a 4 by 4 matrix row by row:");
     
             int[][] matrix = new int[4][4];
     
             for (int i = 0; i < matrix.length; i++)
                for (int j = 0; j < matrix[i].length; j++)
                   matrix[i][j] = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter an integer for the matrix.");
     
     
           JOptionPane.showMessageDialog(null, "Sum of the Matrix is "	+ sumMatrix(matrix));
           //   double sum = sumMatrix(matrix);
          }
          public static double sumMatrix(int[][] m) {
             int sum = 0;
     
             for (int i = 0; i < m.length; i++)
                for (int j = 0; j < m[i].length; j++)
                   sum = sum + m[i][j];
     
             return sum;
          }  
       }


    JOptionPane (Java Platform SE 6)

  3. #3
    Member Java Neil's Avatar
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    Default Re: Summing a 4X4 Matrix in JOptionPane

    Good catch! Thanks...

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    Default Re: Summing a 4X4 Matrix in JOptionPane

    In thinking about this some more I think I need to store each inputs index and recall that index at the end to "Echo the inputs as a[0] = xx, a[1] = xx, a[3] = xx, a[4] = xx, then displays the reslutl"

    maybe something like
     [0] = Double.parseDouble(JOptionPane.showInputDialog(null, "1st number" + " "));
    16 times.

    What do you think? I just need to echo the input at the end of the program, and I can't think of another way to do it.

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    Member Java Neil's Avatar
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    Default Re: Summing a 4X4 Matrix in JOptionPane

    Quote Originally Posted by Java Neil View Post
    In thinking about this some more I think I need to store each inputs index and recall that index at the end to "Echo the inputs as a[0] = xx, a[1] = xx, a[3] = xx, a[4] = xx, then displays the reslutl"

    maybe something like
     [0] = Double.parseDouble(JOptionPane.showInputDialog(null, "1st number" + " "));
    16 times.

    What do you think? I just need to echo the input at the end of the program, and I can't think of another way to do it.
    Well I've messed around with this for hours, and I'm pretty sure this is not how to do this...Once again, I need some help storing the user input and echoing this input at the same time as the sum of the matrix is given. Everything I have tried has either caused errors and would not compile, or has caused logical errors.

    Please help!

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