Description

This application demonstrates the use of the button control of Microsoft Windows. It does this while calculating the factorial, the permutation, and the combinatorial.

Windows Controls:

• Label
• Button
• Text Box
• Tab Control

1. Start NetBeans
2. To create a new application, on the main menu, click File -> New Project...
3. In the first page of the wizard, make sure Java then Java Application is selected. Click Next
4. In the Project Name, type Algebra1
5. Clear the Create Main Class check box
6. Click Finish
7. In the Projects window, right-click Algebra1 -> New -> JFrame Form...
8. Set the Class Name to Central
9. In the Package box, type Accessories
10. Click Finish
11. In the Projects window, right-click Algebra1 -> New -> Java Class...
12. Set the Class Name to Factors
13. In the Package box, type Algebra
14. Click Finish
15. Change the file as follows:
     

    using System; namespace Algebra2 { public class Algebra { public static long Factorial(long x) { if (x <= 1) return 1; else return x * Factorial(x - 1); } public static long Permutation(long n, long r) { if (r == 0) return 0; if (n == 0) return 0; if ((r >= 0) && (r <= n)) return Factorial(n) / Factorial(n - r); else return 0; } public static long Combinatorial(long a, long b) { if (a <= 1) return 1; return Factorial(a) / (Factorial(b) * Factorial(a - b)); } } }

16. In the Projects window, double-click Central
17. In the Properties window, change the following characteristics:
    title: Factorial, Permutation, and Combination
    preferedSize: 304, 208
18. In the Swing Containers section of the Palette, click Tabbed Pane
19. Click the form
20. In the Swing section of the Palette, click Panel
21. Click the tabbed pane on the form
22. Complete the design as follows:
     

    Control Text Name JTabbedPane   jtfAlgebra JPanel Factorial jpFactorial JLabel Number:   JTextField 0  jtfFactorialNumber JButton Calculate jbCalculateFactorial JLabel Result:   JTextField   jtfFactorialResult

23. In the Swing section of the Palette, click Panel
24. On the form, click on the right side of the Factorial tab
25. Continue the design as follows:
     

    Control Text Name JPanel Permutation jpPermutation JLabel n:   JTextField 0 jtfPermutationN JLabel  r:   JTextField  0 jtfPermutationR Button Calculate jbCalculatePermutation JLabel Result:   JTextField 0 jtfPermutationResult

26. In the Swing section of the Palette, click Panel
27. On the form, click on the right side of the Permutation tab
28. Continue the design as follows:
     

    Control Text Name JPanel Permutation jpCombination JLabel n:   JTextField 0 jtfCombinationNumber JLabel  r:   Button Calculate jbCalculateCombination JLabel Result:   JTextField 0 jtfPermutationResult

29. Access the Factorial tab page
30. Right-click its Calculate button -> Events -> Action -> actionPerformed
31. Implement the event as follows:
     

    package Accessories; import javax.swing.JOptionPane; import Algebra.Factors; public class Central extends javax.swing.JFrame { . . . No Change private void jbFactorialCalculateActionPerformed(java.awt.event.ActionEvent evt) { long number = 0; long result; try { number = Long.parseLong(jtfFactorialNumber.getText()); result = Algebra.Factors.Factorial(number); jtfFactorialResult.setText(Long.toString(result)); } catch(Exception exc) { JOptionPane.showMessageDialog(null, "Invalid Number"); } }

32. Click the Design button to return to the form
33. Access the Permutation tab page and double-click its Calculate button
34. Implement the event as follows:
     

    private void jbCalculatePermutationActionPerformed(java.awt.event.ActionEvent evt) { long n = 0, r = 0; long result; try { n = Long.parseLong(jtfPermutationN.getText()); } catch(Exception exc) { JOptionPane.showMessageDialog(null, "Invalid Number"); } try { r = Long.parseLong(jtfPermutationR.getText()); result = Algebra.Factors.Permutation(n, r); jtfPermutationResult.setText(Long.toString(result)); } catch(Exception exc) { JOptionPane.showMessageDialog(null, "Invalid Number"); } }

35. Return to the form
36. Access the Combination tab page and double-click its Calculate button
37. Implement the event as follows:
     

    private void jbCalculateCombinationActionPerformed(java.awt.event.ActionEvent evt) { long n = 0, r = 0; long result; try { n = Long.parseLong(jtfCombinationN.getText()); } catch(Exception exc) { JOptionPane.showMessageDialog(null, "Invalid Number"); } try { r = Long.parseLong(jtfCombinationR.getText()); result = Algebra.Factors.Combinatorial(n, r); jtfCombinationResult.setText(Long.toString(result)); } catch(Exception exc) { JOptionPane.showMessageDialog(null, "Invalid Number"); } }

38. Return to the form
39. Add a JButton and change its characteristics as follows:
    title: Close
    name: jbClose
40. Double-click the button
41. Implement the event as follows:
     

    private void jbCloseActionPerformed(java.awt.event.ActionEvent evt) { dispose(); }

42. Press F6 to execute the application
43. Test the calculations with different values:
     
44. Close the form and return to your programming environment