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How to account for input errors in calculator program?

I'm writing a calculator program for my java class. I want to account for errors like
User decides to divide by 0. I want the calculator to be able to acknowledge this error and display ERROR.
The user enters 6+7+ and then hits the equal button.
I want, once again, for the calculator to acknowledge that there is an error. I was hoping I could get some hints as to how to go about this. Thanks!
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Calculator
{
JFrame window;
// stuff for top panel
JPanel topPanel;
JTextField expr,result;
JButton equals;
// stuff for bottom panel
JPanel bottomPanel,digitsPanel,opsPanel;
JButton[] digits,ops;
JButton clear, clearEntry;
Container content;
Listener listener;
String[] oplabels = { "+", "-", "/", "*" };
public Calculator()
{
listener = new Listener(); // our Listener class implements ActionListener
window= new JFrame("GUI Calc");
content=window.getContentPane();
content.setLayout( new GridLayout(2,1) );
topPanel=new JPanel();
topPanel.setLayout( new GridLayout(1,3) );
// TOP PANEL WORK
expr = new JTextField( );
equals = new JButton("=");
equals.addActionListener( listener );
result = new JTextField( );
topPanel.add( expr );
topPanel.add( equals );
topPanel.add( result );
// BOTTOM PANEL WORK
bottomPanel = new JPanel();
bottomPanel.setLayout( new GridLayout(1,2) );
digitsPanel = new JPanel();
digitsPanel.setLayout( new GridLayout(4,3) );
opsPanel = new JPanel();
opsPanel.setLayout( new GridLayout(4,1) );
digits = new JButton[12];
ops = new JButton[4];
for (int i=0 ; i<10 ; i++)
{
digits[i] = new JButton( i+"" );
digits[i].addActionListener(listener);
digitsPanel.add( digits[i] );
}
clear = new JButton( "C" );
clearEntry = new JButton( "CE" );
clear.addActionListener(listener);
clearEntry.addActionListener(listener);
digitsPanel.add( clear );
digitsPanel.add( clearEntry);
for (int i=0 ; i<4 ; i++)
{
ops[i] = new JButton( oplabels[i] ) ;
ops[i].addActionListener(listener);
opsPanel.add( ops[i] );
}
bottomPanel.add( digitsPanel );
bottomPanel.add( opsPanel );
content.add( topPanel);
content.add( bottomPanel);
window.setVisible(true);
}
class Listener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
Component clicked = (Component) e.getSource();
if ( clicked == equals )
{
result.setText( evaluate( expr.getText() ) );
return;
}
for ( int i=0 ; i<10 ; i++)
{
if ( clicked == digits[i] )
{
expr.setText( expr.getText() + i );
return;
}
}
if ( clicked == clear )
{
expr.setText("0");
return;
// do something
}
/* if (clicked == clearEntry)
{
expr.setText(expr.getDigits[i]);
}
for (int i=0; i < 10; i++)
{
if (clicked == digits[i])
{
int lastValue = clicked;
if(clicked == clearEntry)
{
expr.setText(expr.getText()-clicked);
return;
}
}
} */
for ( int i=0 ; i<4 ; i++ )
{
if(clicked == digits[i])
{
expr.setText(expr.getText() + oplabels[i]);
return;
}
// tack on that operator to the expr string
}
}
String evaluate( String exp )
{
return "NOT WRITTEN YET";
}
}
public static void main(String [] args)
{
new Calculator();
}
}
I'm still working on it. Especially where I'm trying to figure out the clearEntry button so I have put that section as a comment because its still a work in progress.

You can try this:
add a new class(Calculator) member:
Component last_clicked;
Inside Constructor:
last_clicked=null;
Before every return statement of actionPerformed, you can add this:
last_clicked=clicked;
Now, in actionPerformed method, when checking value of clicked, you can do this:
When clicked is '0' & last_clicked is '/', you can display error 1.
When clicked is 'equals' & last_clicked is an operator, you can display error 2.

Can someone help me work out the kinks in my program? [closed]

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Closed 8 years ago.
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I have to write a calculator program using the Gui components. I have written the program but I'm having issues with my CE button. It is giving me errors. I'm also getting and error in my for loop where I add the operand labels to the expression. I was just hoping to get some help in fixing these errors. Thank you! Please ignore the comments. They are there for my to keep track of what I have to do.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Calculator
{
JFrame window;
// stuff for top panel
JPanel topPanel;
JTextField expr,result;
JButton equals;
// stuff for bottom panel
JPanel bottomPanel,digitsPanel,opsPanel;
JButton[] digits,ops;
JButton clear, clearEntry;
Container content;
Listener listener;
String[] oplabels = { "+", "-", "/", "*" };
public Calculator()
{
listener = new Listener(); // our Listener class implements ActionListener
window= new JFrame("GUI Calc");
content=window.getContentPane();
content.setLayout( new GridLayout(2,1) );
topPanel=new JPanel();
topPanel.setLayout( new GridLayout(1,3) );
// TOP PANEL WORK
expr = new JTextField( );
equals = new JButton("=");
equals.addActionListener( listener );
result = new JTextField( );
topPanel.add( expr );
topPanel.add( equals );
topPanel.add( result );
// BOTTOM PANEL WORK
bottomPanel = new JPanel();
bottomPanel.setLayout( new GridLayout(1,2) );
digitsPanel = new JPanel();
digitsPanel.setLayout( new GridLayout(4,3) );
opsPanel = new JPanel();
opsPanel.setLayout( new GridLayout(4,1) );
digits = new JButton[12];
ops = new JButton[4];
for (int i=0 ; i<10 ; i++)
{
digits[i] = new JButton( i+"" );
digits[i].addActionListener(listener);
digitsPanel.add( digits[i] );
}
clear = new JButton( "C" );
clearEntry = new JButton( "CE" );
clear.addActionListener(listener);
clearEntry.addActionListener(listener);
digitsPanel.add( clear );
digitsPanel.add( clearEntry);
for (int i=0 ; i<4 ; i++)
{
ops[i] = new JButton( oplabels[i] ) ;
ops[i].addActionListener(listener);
opsPanel.add( ops[i] );
}
bottomPanel.add( digitsPanel );
bottomPanel.add( opsPanel );
content.add( topPanel);
content.add( bottomPanel);
window.setVisible(true);
}
class Listener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
Component clicked = (Component) e.getSource();
if ( clicked == equals )
{
result.setText( evaluate( expr.getText() ) );
return;
}
for ( int i=0 ; i<10 ; i++)
{
if ( clicked == digits[i] )
{
expr.setText( expr.getText() + i );
return;
}
}
if ( clicked == clear )
{
expr.setText("0");
return;
// do something
}
for (int i=0; i < 10; i++)
{
if (clicked == digits[i])
{
int lastValue = i;
return;
}
}
if ( clicked == clearEntry )
{
expr.setText(expr.getText() - lastValue);
return;
// do something
}
for ( int i=0 ; i<4 ; i++ )
{
if(clicked == oplabels[i])
{
expr.setText(expr.getText + oplabels[i]);
return;
}
// tack on that operator to the expr string
}
}
String evaluate( String exp )
{
return "NOT WRITTEN YET";
}
}
public static void main(String [] args)
{
new Calculator();
}
}

Problem #1
The compiler is complaining about expr.setText(expr.getText() - lastValue); because lastValue is undefined.
Having a close look at the code, the only place that lastValue is defined is within the for-loop before the if statement...but the next issues thereturn` statement following it's decleration...
for (int i = 0; i < 10; i++) {
if (clicked == digits[i]) {
int lastValue = i;
return;
}
}
if (clicked == clearEntry) {
expr.setText(expr.getText() - lastValue);
return;
// do something
}
This not only makes the lastValue useless, but it's unlikely that the if statement would ever be reached...
Problem #2
for (int i = 0; i < 4; i++) {
if (clicked == oplabels[i]) {
expr.setText(expr.getText + oplabels[i]);
return;
}
// tack on that operator to the expr string
}
clicked is defined as Component clicked = (Component) e.getSource(); and oplables are defined as String[] oplabels = {"+", "-", "/", "*"};. String and Component are not comparable (also, you want expr.getText() not expr.getText).
I think you want to do something more like...
if (clicked instanceof JButton) {
JButton btn = (JButton)clicked)
for (int i = 0; i < oplabels.length; i++) {
if (oplabels[i].equals(btn.getText()) {
//...
}
}
}

Line 128: clicked is a Component and oplabels[i] is a string - you can't compare them directly.
Line 130: Missing () on getText() call.

didn't understand action listner of radio buttons

when i click adjacent two radio button then a line drawn between these button i put conditions in my code that line only will draw when two horizontal or vertical radio button selected else it show a error message ........... it works for me but if i click randomly two radio button it will throw an exception which i cant understand please give some discription about answer because i am beginner too............ and what is this means it shows when i compile prog..........Note: C:\Users\MUHAMMAD Umair\Desktop\ComponentLinkerTest.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Map;
import java.util.*;
/**
* #see http://stackoverflow.com/a/12389479/909085
*/
public class ComponentLinkerTest extends JComponent
{
// private Map<JComponent, JComponent> linked;
Map<JComponent, java.util.List<JComponent> > linked;// = new HashMap<>();
int n=1;
public ComponentLinkerTest ()
{
super ();
linked = new HashMap ();
}
static JRadioButton[] button = new JRadioButton[25];
public void gui()
{
setupLookAndFeel ();
JFrame frame = new JFrame ();
linker = new ComponentLinkerTest ();
frame.setGlassPane ( linker );
linker.setVisible ( true );
JPanel content = new JPanel ();
content.setLayout ( new GridLayout ( 5, 5, 5, 5 ) );
content.setBorder ( BorderFactory.createEmptyBorder ( 5, 5, 5, 5 ) );
frame.add ( content );
int i;
for (i = 0; i < 25; i++ )
{
// final JButton button = new JButton ( "Button" + i );
button[i] = new JRadioButton();
// panel.add(fontButtons[i]);
button[i].addActionListener ( new ActionListener ()
{
public void actionPerformed ( ActionEvent e )
{
link ((JRadioButton) e.getSource() );
}
} );
content.add ( button [i]);
}
frame.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
frame.pack ();
frame.setLocationRelativeTo ( null );
frame.setVisible ( true );
}
/*public void link ( JComponent c1, JComponent c2 )
{
linked.put ( c1, c2 );
repaint ();
}*/
public void link ( JComponent c1, JComponent c2 )
{
if(linked.containsKey(c1)){
linked.get(c1).add(c2);
}else{
java.util.List<JComponent> list = new LinkedList<>();
list.add(c2);
linked.put ( c1, list );
}
repaint ();
}
/* protected void paintComponent ( Graphics g )
{
Graphics2D g2d = ( Graphics2D ) g;
g2d.setRenderingHint ( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
g2d.setPaint ( Color.BLACK );
for ( JComponent c1 : linked.keySet () )
{
Point p1 = getRectCenter ( getBoundsInWindow ( c1 ) );
Point p2 = getRectCenter ( getBoundsInWindow ( linked.get ( c1 ) ) );
/* Stroke stroke = new BasicStroke(8//,
/*BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0,
new float[] { 12, 12 }, 0);
g2d.setStroke(stroke);
g2d.setColor(Color.RED);
g2d.drawLine ( p1.x, p1.y, p2.x, p2.y );
}
}*/
#Override
protected void paintComponent ( Graphics g )
{
super.paintComponent(g);
Graphics2D g2d = ( Graphics2D ) g;
g2d.setRenderingHint ( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
g2d.setPaint ( Color.BLACK );
for ( JComponent c1 : linked.keySet () )
{
for(JComponent c2 : linked.get(c1)){
Point p1 = getRectCenter ( getBoundsInWindow ( c1 ) );
Point p2 = getRectCenter ( getBoundsInWindow ( c2 ) );
/* Stroke stroke = new BasicStroke(8//,
/*BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0,
new float[] { 12, 12 }, 0);
g2d.setStroke(stroke);*/
if(n==1)
{
g2d.setColor(Color.RED);
n=2;
}
else
{
g2d.setColor(Color.BLUE);
n=1;
}
g2d.drawLine ( p1.x, p1.y, p2.x, p2.y );
}
}
}
private Point getRectCenter ( Rectangle rect )
{
return new Point ( rect.x + rect.width / 2, rect.y + rect.height / 2 );
}
private Rectangle getBoundsInWindow ( Component component )
{
return getRelativeBounds ( component, getRootPaneAncestor ( component ) );
}
private Rectangle getRelativeBounds ( Component component, Component relativeTo )
{
return new Rectangle ( getRelativeLocation ( component, relativeTo ),
component.getSize () );
}
private Point getRelativeLocation ( Component component, Component relativeTo )
{
Point los = component.getLocationOnScreen ();
Point rt = relativeTo.getLocationOnScreen ();
return new Point ( los.x - rt.x, los.y - rt.y );
}
private JRootPane getRootPaneAncestor ( Component c )
{
for ( Container p = c.getParent (); p != null; p = p.getParent () )
{
if ( p instanceof JRootPane )
{
return ( JRootPane ) p;
}
}
return null;
}
public boolean contains ( int x, int y )
{
return false;
}
private static ComponentLinkerTest linker;
public static void main ( String[] args )
{
ComponentLinkerTest ct = new ComponentLinkerTest();
ct.gui();
}
private static JRadioButton last = null;
private static void link ( JRadioButton buton )
{
int a=0;
int i;
if ( last == null )
{
last = buton;
System.out.println(last.getX());
}
else
{
for( i=0 ;i<25 ;i++)
{
if(buton == button[i])
{
if(button[i-1] == last || button[i+1]==last || button[i-5] == last || button[i+5]==last)
{
System.out.println("in cond");
linker.link ( last, buton );
buton.setSelected(false);
last.setSelected(false);
last = null;
}
else
{
System.out.println("out cond");
buton.setSelected(false);
last.setSelected(false);
last = null;
JOptionPane.showMessageDialog(null,"Wrong position clicked ");
}
break;
}
else
{
System.out.println("button not found");
}
}
}
}
private static void setupLookAndFeel ()
{
try
{
UIManager.setLookAndFeel ( UIManager.getSystemLookAndFeelClassName () );
}
catch ( ClassNotFoundException e )
{
e.printStackTrace ();
}
catch ( InstantiationException e )
{
e.printStackTrace ();
}
catch ( IllegalAccessException e )
{
e.printStackTrace ();
}
catch ( UnsupportedLookAndFeelException e )
{
e.printStackTrace ();
}
}
}

You do no range checking...
This is going to cause an exception if you the last button is the on the last line, or the second button is one the first row
if (button[i - 1] == last || button[i + 1] == last || button[i - 5] == last || button[i + 5] == last)
You need to modify your checks to ensure that they don't extend below (0) or beyond (button.length - 1)...
if ((i > 0 && button[i - 1] == last) ||
(i < (button.length - 1) && button[i + 1] == last) ||
(i > 5 && button[i - 5] == last) ||
(i < (button.length - 1) && button[i - 5] == last)) {
Updated with alternative
Okay, that if statement was doing my head...so I took a different tact...
Basically, instead, I found the index of each button and calculated the distance that each button was from each other, they could only be 1 or 5 indices apart...
int lastIndex = indexOf(last);
int currentIndex = indexOf(buton);
int diff = Math.max(lastIndex, currentIndex) - Math.min(lastIndex, currentIndex);
if (diff == 1 || diff == 5) {
System.out.println("in cond");
linker.link(last, buton);
buton.setSelected(false);
last.setSelected(false);
last = null;
} else {
System.out.println("out cond");
buton.setSelected(false);
last.setSelected(false);
last = null;
JOptionPane.showMessageDialog(null, "Wrong position clicked ");
}
And the indexOf method...
protected static int indexOf(JRadioButton btn) {
int index = -1;
for (int value = 0; value < button.length; value++) {
if (button[value].equals(btn)) {
index = value;
break;
}
}
return index;
}
As a side note, I'd also beware of over using static. This suggest a bad design

adding listeners to JButton array;

I have the following code which creates a JButton array on button click. Ope[] is publically declared in class. I have problem that I got null pointer. That is it doesn't print 2nd in loop ie. doesn't go in inner iteration.
Please tell me how to handle the listeners for array. Thanks in advance.
for( int i=0,y=30; i<counter;i++,y+=15 )
{
open[i]=new JButton( "Open" );
open[i].setBounds( 380, y, 70, 15 );
open[i].addActionListener( this );
panelDisplay.add (open[i] );
System.out.println(""+i);
}
The event handling in actionPerformed function is as follows:
for( int j=0; j<open.length; j++ )
{
System.out.println("1st in a loop"+j);
if( ae.getSource() != null )
{
if( ae.getSource() == open[j] )
{
System.out.println("2nd in a loop" +j);
int id;
String stringid;
System.out.println("open of"+j+"is clicked");
stringid = ""+table.getValueAt(j, 0);
id = Integer.parseInt(stringid);
fetchData(id);
//ae.getSource().equals(null);
}
}
}

JButton inherits "setName" Method from Component. So if you set a name on the Button at initialization
open[i]=new JButton( "Open" );
open[i].setBounds( 380, y, 70, 15 );
open[i].setName("Button"+i);
open[i].addActionListener( this );
panelDisplay.add (open[i] );
System.out.println(""+i);
you can find wich button was pressed in the eventhandling
int buttonNumber = Integer.parseInt(ae.getSource().getName().replace("Button",""))
//... do eventhandling for Button["buttonNumber"]

Swing: popover with arrow

I'd like to create a Google Chrome favorites-style popover with arrow, rounded corners and if I have time a shadow effect. In Java Swing. What is the best approach? SplashScreen? Or just a plain AWT Window? Other ideas? Thanks!

There are a few options and each of them has its own pros and cons...
Create a custom-shaped window - with this approach some systems will be able to create additional shade behind the shaped window, also this works on most of systems (should work even on linux JDK's). The bad thing about this approach (that actually makes it unusable) is the unaliased shape border line - if you create some ellipse-shaped window its sides will appear rough.
Create a non-opaque undecorated window with drawn shape - this approach will fix the main problem of the (1) approach. You can alias shape you re drawing on fully transparent window. The bad thing about this one is that it works only on Win and Mac systems. On (mostly) any linux system you will get a rectangle resulting window and tons of errors about unsupported operations.
Create a custom-shaped popup inside the java-window and place it on the window layered or glass panes. This will allow you to fully avoid any compatibility problems and get the benefits of the (2) approach. There is a bad thing about this approach though - you can only display such popup in window root pane bounds. This is still much better than two other ways in most of cases, since it uses less resources, does not create additional windows and you can control every part of the popup.
About the 3rd approach - you can check TooltipManager i have created in my own project WebLookAndFeel - it uses window glass pane to display custom-shaped semi-transparent tooltips with a shadow-effect. Also soon enough i will add window PopupManager that will allow quick creation of "inner" window popups.
Here are some examples of the approaches:
A bit of code that used ahead in all of the examples
Method to create shape:
private static Area createShape ()
{
Area shape = new Area ( new RoundRectangle2D.Double ( 0, 20, 500, 200, 20, 20 ) );
GeneralPath gp = new GeneralPath ( GeneralPath.WIND_EVEN_ODD );
gp.moveTo ( 230, 20 );
gp.lineTo ( 250, 0 );
gp.lineTo ( 270, 20 );
gp.closePath ();
shape.add ( new Area ( gp ) );
return shape;
}
Mouse adapter that allows to move window by dragging the component:
public static class WindowMoveAdapter extends MouseAdapter
{
private boolean dragging = false;
private int prevX = -1;
private int prevY = -1;
public WindowMoveAdapter ()
{
super ();
}
public void mousePressed ( MouseEvent e )
{
if ( SwingUtilities.isLeftMouseButton ( e ) )
{
dragging = true;
}
prevX = e.getXOnScreen ();
prevY = e.getYOnScreen ();
}
public void mouseDragged ( MouseEvent e )
{
if ( prevX != -1 && prevY != -1 && dragging )
{
Window w = SwingUtilities.getWindowAncestor ( e.getComponent () );
if ( w != null && w.isShowing () )
{
Rectangle rect = w.getBounds ();
w.setBounds ( rect.x + ( e.getXOnScreen () - prevX ),
rect.y + ( e.getYOnScreen () - prevY ), rect.width, rect.height );
}
}
prevX = e.getXOnScreen ();
prevY = e.getYOnScreen ();
}
public void mouseReleased ( MouseEvent e )
{
dragging = false;
}
}
1st approach example:
public static void main ( String[] args )
{
JFrame frame = new JFrame ();
frame.setUndecorated ( true );
JPanel panel = new JPanel ();
panel.setBackground ( Color.BLACK );
WindowMoveAdapter wma = new WindowMoveAdapter ();
panel.addMouseListener ( wma );
panel.addMouseMotionListener ( wma );
frame.getContentPane ().add ( panel );
Area shape = createShape ();
AWTUtilities.setWindowShape ( frame, shape );
frame.setSize ( shape.getBounds ().getSize () );
frame.setLocationRelativeTo ( null );
frame.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
frame.setVisible ( true );
}
As you can see - corners of the rounded shape are pretty rough and not good-looking
2nd approach:
public static void main ( String[] args )
{
JFrame frame = new JFrame ();
frame.setUndecorated ( true );
final Area shape = createShape ();
JPanel panel = new JPanel ()
{
protected void paintComponent ( Graphics g )
{
super.paintComponent ( g );
Graphics2D g2d = ( Graphics2D ) g;
g2d.setRenderingHint ( RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON );
g2d.setPaint ( Color.BLACK );
g2d.fill ( shape );
}
};
panel.setOpaque ( false );
WindowMoveAdapter wma = new WindowMoveAdapter ();
panel.addMouseListener ( wma );
panel.addMouseMotionListener ( wma );
frame.getContentPane ().add ( panel );
AWTUtilities.setWindowOpaque ( frame, false );
frame.setSize ( shape.getBounds ().getSize () );
frame.setLocationRelativeTo ( null );
frame.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
frame.setVisible ( true );
}
Now it should look perfect - the only problem this will properly work only on Windows and Mac (atleast in 1.6.x JDK). Atleast it was so about a month ago when i last time checked it on various OS.
3rd approach
public static void main ( String[] args )
{
JFrame frame = new JFrame ();
JPanel panel = new JPanel ( new BorderLayout () );
panel.setOpaque ( false );
WindowMoveAdapter wma = new WindowMoveAdapter ();
panel.addMouseListener ( wma );
panel.addMouseMotionListener ( wma );
frame.getContentPane ().add ( panel );
panel.add ( new JButton ( "Test" ) );
final Area shape = createShape ();
JPanel glassPane = new JPanel ( null )
{
public boolean contains ( int x, int y )
{
// This is to avoid cursor and mouse-events troubles
return shape.contains ( x, y );
}
};
glassPane.setOpaque ( false );
frame.setGlassPane ( glassPane );
glassPane.setVisible ( true );
JComponent popup = new JComponent ()
{
protected void paintComponent ( Graphics g )
{
super.paintComponent ( g );
Graphics2D g2d = ( Graphics2D ) g;
g2d.setRenderingHint ( RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON );
g2d.setPaint ( Color.BLACK );
g2d.fill ( shape );
}
};
popup.addMouseListener ( new MouseAdapter ()
{
// To block events on the popup
});
glassPane.add ( popup );
popup.setBounds ( shape.getBounds () );
popup.setVisible ( true );
frame.setSize ( 800, 500 );
frame.setLocationRelativeTo ( null );
frame.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
frame.setVisible ( true );
}
This is a simple example of the popup placed on glass-pane. As you can see it exists only inside of the JFrame, but has the aliased side and works properly on any type of OS.