Java Applet

[mex2005]

Ok so i was given the task to create a java applet in which you type a number, and then check if the number is Perfect, Deficient, Abundant and Prime.

Here is the source text of the java console application i wrote:

import java.util.Scanner;

public class NumberTester
{
public static void main (String[] args)
{
Scanner console = new Scanner (System.in);
int n;
n = console.nextInt();
if (isPerfectNumber (n))
System.out.println (" " + n + " Perfect");
else 
System.out.println (" " + n + " Not Perfect");

if (isDeficientNumber (n))
System.out.println (" " + n + " Deficient");
else 
System.out.println (" " + n + " Not Deficient");

if (isDeficientNumber (n))
System.out.println (" " + n + " Abundant");
else 
System.out.println (" " + n + " Not Abundant");

if (isAbundantNumber (n))
System.out.println (" " + n + " Prime");
else 
System.out.println (" " + n + " Not Prime");

}
private static boolean isPerfectNumber (int n) {
int total = 0;
for (int i=1; i<n; i++) 
if (n % i == 0) total += i;
return (total == n);
}

private static boolean isDeficientNumber (int n) {
int total = 0;
for (int i=1; i<n; i++) 
if (n % i == 0) total += i;
return (total < n);
}

private static boolean isAbundantNumber (int n) {
int total = 0;
for (int i=1; i<n; i++) 
if (n % i == 0) total += i;
return (total > n);
}
private static boolean isPrimeNumber (int n) {
for(int i=3;i*i<=n;i+=2) {
if(n%i==0)
return false;
}
return true;
}
}

I have no idea how to turn it into an applet. Can somebody please help me with it, I'm still a beginner.

[travishein]

well, the hard part of doing the number processing to determine if the number is the abundant, deficient, prime is done. Now you just need to applet-ize that.

How about taking a look at some existing applet that has a kind of input and push button to compute some output, like this Celsius Fahrenheit conversion Java applet sample

[al_Marshy_1981]

you do have google though
Lesson: Applets (The Java™ Tutorials > Deployment)

[mex2005]

Well i tried to look at an example of an applet to get the idea, but I still can't get it even close to working. Problem is i need it for tomorrow, but i'm going to try it again with that celciustofarenheit example.
Thanks.

[al_Marshy_1981]

What problems are you running into exactly with the applet implementation?

[mex2005]

Well this is what i came up with for just one type of number:

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Tester5 extends Applet implements ActionListener{
TextField txtNumber;
Label lblNumber;
Button cmdTest;

public void init(){
lblNumber = new Label("Enter the Number: ");
add(lblNumber);
txtNumber = new TextField(5);
add(txtNumber);
cmdNumber = new Button("Test");
add(cmdNumber);
cmdNumber.addActionListener(this);
}



public void actionPerformed(ActionEvent e){
private static boolean isPerfectNumber (int n) {

String str; int n;
str = txtNumber.getText();
n = Integer.parseInt(str);
int total = 0;
for (int i=1; i<n; i++) 
if (n % i == 0) total += i;
return (total == n);
}

public void paint(Graphics g)
    {
    	g.clearRect(0, 50, 200, 80);
				
			if (isPerfectNumber (n))
       		g.drawString("" + n + " is perfect", 10, 60);
       	else
       		g.drawString("" + n + " is not perfect ", 10, 60);
				

}
}
}

these are the errors i'm getting:

Tester5.java:23: illegal start of expression
private static boolean isPerfectNumber (int n) {
^
Tester5.java:23: illegal start of expression
private static boolean isPerfectNumber (int n) {
^
Tester5.java:23: ';' expected
private static boolean isPerfectNumber (int n) {
^
Tester5.java:23: '.class' expected
private static boolean isPerfectNumber (int n) {
^
Tester5.java:23: ';' expected
private static boolean isPerfectNumber (int n) {
^
Tester5.java:34: illegal start of expression
public void paint(Graphics g)
^
Tester5.java:34: illegal start of expression
public void paint(Graphics g)
^
Tester5.java:34: ';' expected
public void paint(Graphics g)
^
Tester5.java:34: ';' expected
public void paint(Graphics g)
^
9 errors

----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.

[al_Marshy_1981]

This really does pain me to say but can you please put your code in tags?

[code]
// your code

[/cod] but with an 'e' after 'd' to make the word code ok?

[al_Marshy_1981]

semi colon problem? ;

re-investigate your code...compiler don't lie

[mex2005]

This isn't very helpful...

[al_Marshy_1981]

what is not helpful?

[travishein]

well, you can't have the methods private static boolean isPerfectNumber (int n) and
public void paint(Graphics g) inside the actionPerformed() method..

[travishein]

also, the isPerfect, you cannot declare variable n when parameter is also n.
And its not likely necessary to have the static modifier, that won't be able to read the non static reference. And we shouldn't e reading the text field from the fuction, the action handler should read this. And I believe it is good practice to always use block delimiters { } for single line if and for statements.

well, for example,

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Tester5 extends Applet {
  TextField txtNumber;
  Label lblNumber;
  Button cmdNumber;

  // declare a result text field
  Label resultLabel;
  TextField result;

  public void init() {
    Panel p = new Panel();
    p.setLayout(new GridBagLayout() );
    lblNumber = new Label("Enter the Number: ");
    p.add(lblNumber, new GridBagConstraints(0,0,1,1,1.0,1.0,GridBagConstraints.EAST,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));

    txtNumber = new TextField(5);
    p.add(txtNumber, new GridBagConstraints(1,0,1,1,2.0,1.0,GridBagConstraints.WEST,GridBagConstraints.HORIZONTAL,new Insets(2,2,2,2),4,0));

    cmdNumber = new Button("Is Perfect Number?");
    p.add(cmdNumber, new GridBagConstraints(0,1,2,1,1.0,1.0,GridBagConstraints.CENTER,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));

    resultLabel = new Label("Result: ");
    p.add(resultLabel, new GridBagConstraints(0,2,1,1,1.0,1.0,GridBagConstraints.EAST,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));

    result = new TextField();
    result.setEditable(false);
    p.add(result, new GridBagConstraints(1,2,1,1,2.0,1.0,GridBagConstraints.WEST,GridBagConstraints.HORIZONTAL,new Insets(2,2,2,2),4,0));

    setLayout(new BorderLayout());
    add(p, BorderLayout.CENTER);

    // declare button handler as anonymous inner class.
    cmdNumber.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
          // fetch the text from input
            int input = Integer.parseInt(txtNumber.getText());

          // invoke computation
          boolean perfect = isPerfectNumber(input);

          // put result up
          if (perfect) {
            result.setText("number is perfect");
          }
          else {
            result.setText("number is not perfect");
          }
        }
    });
  }


  private boolean isPerfectNumber (int n) {

    int total = 0;
    for (int i=1; i<n; i++) {
      if (n % i == 0) {
        total += i;
      }
    }
    return (total == n);
  }

}

and then (Tester5.html)

<HTML>
<BODY>
<applet code="Tester5.class",height="200" width="500">
</applet>
</BODY>
</HTML>

and then

   javac Tester5.java
   appletviewer Tester5.html