How to display a grid using dialog box?

Hi could somebody please help me. I am currently making a program that will get the average of the 3 scores of each of the 2 subjects.(math and english). I'm done making the program but the thing that I can't seem to make is how to display it inside a grid using a dialog box. I tried using special alt keys to manually make it but it didn't work. Here's my code:

Code:

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import javax.swing.*;
public class average
{
  public static void main(String[]args)
  {
    int eng1,eng2,eng3,math1,math2,math3;
  double ave1,ave2;
  String S1;
    S1 = JOptionPane.showInputDialog("Enter 1st Quiz Grade in English: ");
    eng1 = Integer.parseInt(S1);
    S1 = JOptionPane.showInputDialog("Enter 2st Quiz Grade in English: ");
    eng2 = Integer.parseInt(S1);
    S1 = JOptionPane.showInputDialog("Enter 3st Quiz Grade in English: ");
    eng3 = Integer.parseInt(S1);
    S1 = JOptionPane.showInputDialog("Enter 3st Quiz Grade in English: ");
    math1 = Integer.parseInt(S1);
    S1 = JOptionPane.showInputDialog("Enter 3st Quiz Grade in English: ");
    math2= Integer.parseInt(S1);
    S1 = JOptionPane.showInputDialog("Enter 3st Quiz Grade in English: ");
    math3 = Integer.parseInt(S1);
  ave1=(math1+math2+math3)/3;
  ave2=(eng1+eng2+eng3)/3;
  JOptionPane.showMessageDialog(null,
                                "\nSubject                      1      2    3"
                              +"\nEnglish      " +"              "+eng1+"    " +eng2+"  "+eng3
                              +"\nMathematics  " +"        "+math1+ "    " +math2+ "  " +math3
                              +"\n Math    Gen Ave"+ave1
                              +"\n English Gen Ave"+ave2,"Report", JOptionPane.INFORMATION_MESSAGE);
}
}

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I think you should remove the + after null, and what is ave ?

ohh sorry forgot to remvoe the + after the null, wait let me fix it. the ave should be only one for each subject hehe

done fixing the bugs. Can somebody teach me how to display it output inside a grid in a dialog box? Thank you