Thread: 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.

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)

Good catch! Thanks...

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.

Originally Posted by Java Neil

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!