Need Help with a JAVA programming assignment
How do I write a JAVA program that could be used as the start of an MS-DOS/Windows simulation of the IEEE 802.3 protocol? I am to only code the parts necessary to build the 802.3 frame. For the initial implementation, the Checksum function need not be a CRC function, and the Destination and Source addresses wil be in input, stored, and output, and in dotted-decimal format.
I need:
1. A record to describe the frame, with each field being a (byte-) string of the required size, except that the Data field is of variable size. Although the "Source address" and "Destination address" would be 6 bytes for a real implementation, for this first implementation you can either assume they'll be text strings in the usual "dotted decimal" form (e.g. "14.04.05.18.01.25" as a typical example--from Tanenbaum, p. 429), or 6 hex digits.
2. Suitable constant declarations for values such as the standard "Preamble" and "Start of Frame" values.
3. Suitable functions to Get the three variable values "Destination address", "Source address", and "Data" from the standard input device.
4. A suitable function to display each of the fields of a given frame in a format such as:
Preamble: ...
StartofFrame: ...
Destination: ...
etc.
5. A suitable function to generate a "Pad" field if necessary.
6. A "dummy" Checksum-generating function which just takes the first 32 bits (4 bytes) of the Data (or Data+Pad, if necessary) rather than an actual CRC algorithm.
I have no experience with Java. Can you help me or start me in the right direction?
Thanks...........TK
If you have no experience with Java, then it seems to me your first step should be to start learning the language. But it's difficult to advise how, since we don't know anything about your background. There are many good books available on Java, some are for beginners and some are for advanced programmers, so I'd suggest you go somewhere that has a large selection and start looking for something that doesn't seem completely over your head.
Similar Messages
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Hey
I am doing a bachelor of Multimedia and for some reason I was forced to do Programming 1 which is just Java programing.I have been doing pretty well but we have the final exam coming up on Thursday and they told us to learn how to do this question but I have no idea how to do it, could someone please help me?
Write a program that reads a file containing a list of students' student numbers and names, and then writes out another file in which the students have been formed into project groups.
Sample input file:
96439530 Naranek, Kosh
08532109 Ivanova, Susan
87642078 Sheridan, John
44327889 Varner, Dell
98100023 Kotto, Vir
66345689 Sinclair, Jeffrey
77421009 Garibaldi, Michael
88775544 Winters, Talia
54321098 Alexander, Lyta
12345098 Mollari, Londo
03465499 Takashima, Laurel
88765432 Kyle, Benjamin
08876500 Keffer, Warren
07687878 Cole, Marcus
For the project course: no group should have more than 5 members; and it is desireable that all groups have as close to 5 members as possible; and that students be allocated to groups alphabetically by family name, as in this sample output file:
Group 1:
Lyta Alexander (54321098)
Susan Ivanova (08532109)
Benjamin Kyle (88765432)
John Sheridan (87642078)
Dell Varner (44327889)
Group 2:
Marcus Cole (07687878)
Warren Keffer (08876500)
Londo Mollari (12345098)
Jeffrey Sinclair (66345689)
Talia Winters (88775544)
Group 3:
Michael Garibaldi (77421009)
Vir Kotto (98100023)
Kosh Naranek (96439530)
Laurel Takashima (03465499)
Students' names are first sorted (Alexander, Cole, Garibaldi, Ivanova, ...), then allocated to the tutes in rotation (Alexander to 1, Cole to 2, Garibaldi to 3, Ivanova to 1, ...).
Note also that the student's details are written in a different format from the input. You may make the (usually wrong!) assumption that each student has a simple one-word family name and one other name.I'm sorry too annoy you again but I don't know how to implement what you told me. Here is my current code:
import java.io.*;
import java.util.*;
class DetailSortTest {
public void run() {
try {
BufferedReader in = new
BufferedReader(new FileReader ("Data.txt"));
String line = in.readLine();
String[] names = new String [10];
int i = 0;
PrintWriter FileOut = new
PrintWriter(new FileWriter ("Data 2.txt"));
processFilesTest(in, FileOut);
in.close();
FileOut.close();
} catch (FileNotFoundException f) {
System.out.println("Could Not Open The File");
} catch (IOException i){
System.out.println(i.getMessage());
public void processFilesTest (BufferedReader in, PrintWriter FileOut)
throws IOException {
String data[] = new String[100];
List dList = new ArrayList();
String NLine = in.readLine();
FileOut.println(NLine);
public static void main(String[] args) {
DetailSortTest anObject = new
DetailSortTest();
anObject.run();
How would I do it I tried:
NLine.split(data[2]+""+data[1]+""+data[0]);
But all that displays is null, null, null
I know I am probably so stupid but I really appreciate the help -
Need help with basic Java programming
I'm having a little bit of trouble with my code. For the sake of argument, I've removed the code I'm having trouble with, because I know it was inaccurate. I'm trying to create a loop so that this program will keep going through and through until the user enters an invalid variable. I thought the default after the case statements was supposed to make the system exit and output my message. Those two problems, the loop and the default, are what I'm really having problems with. My code is posted below.
import javax.swing.JOptionPane;
import java.util.Locale;
import java.text.NumberFormat;
public class Retail
public static void main(String args[])
String firstNum;
String secondNum;
String result;
int prodNum; //first number to input
double quantity; //second number to input
double total = 0.0; //total of Prod * Quantity Sold for all items
// To use American Dollar
NumberFormat moneyFormat = NumberFormat.getCurrencyInstance( Locale.US );
// first number entered as string
firstNum = JOptionPane.showInputDialog( "Enter product number 1-5" );
// second number entered as string
secondNum = JOptionPane.showInputDialog( " Enter quantity of items sold" );
// convert values to type double or int from type string
prodNum = Integer.parseInt( firstNum );
quantity = Double.parseDouble( secondNum);
result="";
if ( prodNum >=1 && prodNum <=5 ) {
switch (prodNum)
case 1: // 1st product
total = 2.98 * quantity;
break;
case 2: // 2nd product
total = 4.50 * quantity;
break;
case 3: // 3rd product
total = 9.98 * quantity;
break;
case 4: //4th product
total = 4.49 * quantity;
break;
case 5:
total = 6.87 * quantity;
break;
default: JOptionPane.showMessageDialog( null, "Wrong product number entered" );
JOptionPane.showMessageDialog( null, moneyFormat.format(total), "Total Price of Items Purchased", JOptionPane.INFORMATION_MESSAGE );
System.exit(0);
***I know I need to put something in the user input message to state that any value other than 1-5 entered will cause the program to skip to the output, I'll put that in later.***When you post code, please use [code] and [/code] tags as described in Formatting Help on the message entry page. It makes it much easier to read and prevents accidental markup from array indices like [i].
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Need Help with a Java programming exercise.
I have to Write a program that reads two times in military format (0900, 1730) and prints the number of hours and minutes between two times. Supply your own test program. Here are two sample runs. User inputs are the numbers.
Please enter the first time: 0900
Please enter the second time: 1730
8 hours 30 minutes
Please enter the first time: 1730
Please enter the second time: 0900
15 hours 30 minutes
Test Program I can write up myself. But the entire constructor I have no idea how to start. This is basic Java Coding. no C++ no importing anything.
So far this is what I got and I'm sure it's wrong:
public class TimeInterval
private double hours;
private double minutes;
public TimeInterval(double Time1, double Time2)
hours =
minutes =
}tad2382 wrote:
Jverd,
I'm guessing that in your early days on this forum you must have spent a lot of time explaining constructors, object creation, etc. Now, after some 40K posts to the forum, you figure newbies should just go and read the documentation. Is that what a lot of veteran posters feel?Perhaps the OP is not aware of the fact the Sun has a good deal of high quality study material published on their website. What's wrong with posting it in a thread? Why should one copy the same thing over and over again? If after reading that tutorial, the OP still has some questions about it, s/he is free to post a follow up question. I am sure that many of the regulars here are more than happy to answer them.
Also note that the OP's problem description is rather vague. A "I don't know where to start" is IMO best answered by a link to a comprehensive tutorial or a beginners book.
Being one of the (relatively) novice posters on the forum, I still feel the need to customize posts,Well, by all means: do so.
trying to see things from the poster's side. Maybe after a few thousand posts, I'll just keep throwing the same documentation at newbies, instead of detailed customized responses, heh.IMO, that's a load of cr@p. -
Need help with a rudimentary program
I'm sort of new at this so i need help with a few things... I'm making a program to compile wages and i need answers with three things: a.) what are the error messages im getting meaning? b.) How can i calculate the state tax as 2% of my gross pay with the first $200 excluded and c.) how can i calculate the local tax as a flat $10 with $2 deducted for each dependant. any help is appreciated
Here is what i have so far:
public class WagesAsign1
public static void main(String[] args)
int depend=4;
double hrsWork=40;
double payRate=15;
double grossPay;
grossPay=payRate*hrsWork;
double statePaid;
double stateTax=2.0;
statePaid=grossPay*(stateTax/100);
double localPaid;
double localTax=10.0;
localPaid=grossPay*(localTax/100);
double fedPaid;
double fedTax=10.0;
double taxIncome;
fedPaid=taxIncome*(fedTax/100);
taxIncome=grossPay-(statePaid+localPaid);
double takeHome;
System.out.println("Assignment 1 Matt Foraker\n");
System.out.println("Hours worked="+hrsWork+" Pay rate $"+payRate+" per/hour dependants: "+depend);
System.out.println("Gross Pay $"+grossPay+"\nState tax paid $"+statePaid+"\nLocal tax paid $"+localPaid+"\nFederal tax paid $"+fedPaid);
System.out.println("You take home a total of $"+takeHome);
and these are the error messages so far:
WagesAsign1.java:23: variable taxIncome might not have been initialized
fedPaid=taxIncome*(fedTax/100);
^
WagesAsign1.java:29: variable takeHome might not have been initialized
System.out.println("You take home a total of $"+takeHome);
^edit: figured it out... please delete post
Message was edited by:
afroryan58 -
Need help with my addressbook program
hi,
i need help with my program here. this one should works as:
- saves user input into a txt file
- displays name of the saved person on the jlist whenever i run the program
- displays info about the person when clicked via textboxes given by reading the txt file where the user inputs are
- should scroll when the list exceeds the listbox
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.JList;
import java.awt.event.ActionListener;
import java.io.*;
import javax.swing.event.*;
import java.io.FilterInputStream;
public class AddressList extends JPanel implements ActionListener
JTextField txt1 = new JTextField();
JTextField txt2 = new JTextField();
JTextField txt3 = new JTextField();
DefaultListModel mdl = new DefaultListModel();
JList list = new JList();
JScrollPane listScroller = new JScrollPane(list);
ListSelectionModel listSelectionModel;
File fob = new File("Address3.txt");
String name;
char[] chars;
public void ListDisplay()
try
RandomAccessFile rand = new RandomAccessFile(fob,"rw");
BufferedReader br = new BufferedReader(new FileReader("Address3.txt"));
if(fob.exists())
while((name = rand.readLine()) != null)
chars = name.toCharArray();
if(chars[0] == '*')
mdl.addElement(name);
list.setModel(mdl);
if(chars[0] == '#')
continue;
else
System.out.println("No such file..");
catch(IOException a)
System.out.println(a.getMessage());
public AddressList()
this.setLayout(null);
listSelectionModel = list.getSelectionModel();
listSelectionModel.addListSelectionListener(new ListInfo());
list.setBounds(10,40,330,270);
listScroller.setBounds(320,40,20,100);
add(list);
add(listScroller);
JLabel lbl4 = new JLabel("Name: ");
lbl4.setBounds(400,10,80,30);
add(lbl4);
JLabel lbl5 = new JLabel("Cellphone #: ");
lbl5.setBounds(400,50,80,30);
add(lbl5);
JLabel lbl6 = new JLabel("Address: ");
lbl6.setBounds(400,90,80,30);
add(lbl6);
JLabel lbl7 = new JLabel("List ");
lbl7.setBounds(10,10,100,30);
add(lbl7);
txt1.setBounds(480,10,200,30);
add(txt1);
txt2.setBounds(480,50,200,30);
add(txt2);
txt3.setBounds(480,90,200,30);
add(txt3);
JButton btn1 = new JButton("Add");
btn1.setBounds(480,130,100,30);
btn1.addActionListener(this);
btn1.setActionCommand("Add");
add(btn1);
JButton btn2 = new JButton("Save");
btn2.setBounds(480,170,100,30);
btn2.addActionListener(this);
btn2.setActionCommand("Save");
add(btn2);
JButton btn3 = new JButton("Cancel");
btn3.setBounds(480,210,100,30);
btn3.addActionListener(this);
btn3.setActionCommand("Cancel");
add(btn3);
JButton btn4 = new JButton("Close");
btn4.setBounds(480,250,100,30);
btn4.addActionListener(this);
btn4.setActionCommand("Close");
add(btn4);
public static void main(String[]args)
JFrame frm = new JFrame("Address List");
AddressList panel = new AddressList();
frm.getContentPane().add(panel,"Center");
frm.setSize(700,350);
frm.setVisible(true);
panel.ListDisplay();
public void actionPerformed(ActionEvent e)
String cmd;
cmd = e.getActionCommand();
if(cmd.equals("Add"))
txt1.setText("");
txt2.setText("");
txt3.setText("");
else if(cmd.equals("Save"))
mdl.addElement(txt1.getText());
list.setModel(mdl);
try
RandomAccessFile rand = new RandomAccessFile(fob,"rw");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
LineNumberReader line = new LineNumberReader(br);
if(fob.exists())
rand.seek(fob.length());
rand.writeBytes("* " + txt1.getText());
rand.writeBytes("\r\n" + "# " + txt2.getText());
rand.writeBytes("\r\n" + "# " + txt3.getText() + "\r\n");
else
System.out.println("No such file..");
txt1.setText("");
txt2.setText("");
txt3.setText("");
catch(IOException a)
System.out.println(a.getMessage());
else if(cmd.equals("Cancel"))
txt1.setText("");
txt2.setText("");
txt3.setText("");
else if(cmd.equals("Close"))
System.exit(0);
class ListInfo implements ListSelectionListener
public void valueChanged(ListSelectionEvent e)
ListSelectionModel lsm = (ListSelectionModel)e.getSource();
int minIndex = lsm.getMinSelectionIndex();
int maxIndex = lsm.getMaxSelectionIndex();
try //*this one should display the info of the person whenever i click the person's name at the list box via textbox.. but i cant seem to get it right since it always display the info of the first person inputed.. i tried to get the program to display them whenever it reads lines with * on them....
File fob = new File("Address3.txt");
RandomAccessFile rand = new RandomAccessFile(fob,"rw");
BufferedReader br = new BufferedReader(new FileReader("Address3.txt"));
LineNumberReader line = new LineNumberReader(br);
if(fob.exists())
for(int i = minIndex; i<=maxIndex; i++)
if(lsm.isSelectedIndex(i))
while((name = rand.readLine()) != null)
chars = name.toCharArray();
if(chars[0] == '#')
continue;
if(chars[0] == '*')
txt1.setText(rand.readLine());
txt2.setText(rand.readLine());
txt3.setText(rand.readLine());
else
System.out.println("No such file..");
catch(IOException a)
System.out.println(a.getMessage());
}the only problem now is about how it should display the right info about the person whenever i click its name on the list.. something about file reading or something, i just cant figure it out.
and also about how to make it scroll once it exceeds the list.. i cant make it work, maybe something about wrong declaration..
thanks in advance..
Edited by: syder on Mar 14, 2008 2:26 AMLike said before, do one thing at a time. At startup, something like:
//put all the content in a list
ArrayList<String> lines = new ArrayList<String>();
while(String line=rand.readLine()!=null) {
lines.add(line);
}If you follow the good advice to create a class to encapsulate the entries, you could populate a list of such entries like this:
static final int ENTRY_SIZE = 3;//you have 3 fields now, better to have a constant if that changes
ArrayList<Entry> entries = new ArrayList<Entry>();
for(int i=0; i<lines.size(); i+=ENTRY_SIZE) {
Entry entry = new Entry(lines.get(i), lines.get(i+1), lines.get(i+2);
entries.add(newEntry);
}You could also do both of the above in one run, but I think you will understand better what's happening if you do one thing at a time.
If you don't want to put the entries in an encapsulating class, you can still access this without looping:
int listStartIdx = <desired_entry_index>*ENTRY_SIZE;
String att1 = lines.get(listStartIdx).substring(1);
String att2 = lines.get(listStartIdx+1).substring(1);
String att3 = lines.get(listStartIdx+2).substring(1); -
Hi, I'm not sure if I'm allowed to post questions on this forum but I can't find anywhere to talk to helpful people about programming.
I'm making a dnd interface for JComponents. So far I've made a simple program that has a Component that can be lifted from a container and braught to the glass pane then later moved to anywhere on the screen and dropped into the container below it. Here's where my problems come:
1) Rite now my 'Movable Component' is a JPanel which is just colored in. I want to either take a Graphic2d from a JComponent/Component and draw it on the JPanel or change the JPanel to the component I want to paint and disable the component.
The problem with getting the Graphics2d is that if the component isn't on the screen it doesn't make a graphic object. I tried messing with the ui delicate and overriding parental methods for paintComponent, repaint, and that repaintChildren(forget name) but I haven't had luck getting a good graphics object. I was thinking of, at the beginning of running the program, putting 1 of each component onto the screen for a second then removing it but I'd rather not. I'd also like to change the graphics dynamicly if someone stretches the component there dropping and what not.
The problem with disabling is that it changes some of the visual features of Components. I want to be able to update the Component myself to change how it looks and I don't want disabling to gray out components.
I mainly just dont want the components to do any of there normal fuctions. This is for a page builder, by the way.
Another problem I'm having is that mouseMotionListener is allowing me to select 2 components that are on top of one another when there edges are near each other. I don't know if theres a fix to this other than changing the Java Class.
My next problem is a drop layout manager, but I'm doing pretty good with that rite now. It'll problem just move components out of the way of the falling component.
One last thing I need help with is that I don't want the object that's being carried to go across the menu bar and certain areas. When I'm having the object being carried I have it braught up to the glass pane which allows it to move anywhere. Does anyone have any idea how I could prevent the component from being over the menu bars and other objects? I might have to make 1 panel is the movable area that can then be broken down into the 'component bank', 'building page' and whatever else I'm gonna need.
This is all just test code to get together for when I make the real program but I need to make sure it'll be possible without a lot of hacking of code.
Sorry for the length. Thanks for any help you can give.The trick to making viewable components that have no behaviour, is to render them onto an image of some sort (eg a BufferedImage). You can then display the Image on a JLabel that can be dragged around the desktop.
Here is a piece of code that does the component rendering for you. This particular example uses a fixed component size, but you can modify that as you choose of course...public class JComponentImage
private static GraphicsConfiguration gConfig;
private static Dimension compSize = new Dimension(80, 22);
private static Image image = null;
public static Image getImage(Class objectClass)
if (gConfig == null)
GraphicsEnvironment gEnv = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gDevice = gEnv.getDefaultScreenDevice();
gConfig = gDevice.getDefaultConfiguration();
image = gConfig.createCompatibleImage(compSize.width, compSize.height);
JComponent jc = (JComponent) ObjectFactory.instantiate(objectClass);
jc.setSize(compSize);
Graphics g = image.getGraphics();
g.setColor(Color.LIGHT_GRAY);
g.fillRect(0, 0, compSize.width, compSize.height);
g.setColor(Color.BLACK);
jc.paint(g);
return image;
}And here is the class that makes the dragable JLabel using the class above...public class Dragable extends JLabel
private static DragSource dragSource = DragSource.getDefaultDragSource();
private static DragGestureListener dgl = new DragMoveGestureListener();
private static TransferHandler th = new ObjectTransferHandler();
private Class compClass;
private Image image;
Dragable(Class compClass)
this.compClass = compClass;
image = JComponentImage.getImage(compClass);
setIcon(new ImageIcon(image));
setTransferHandler(th);
dragSource.createDefaultDragGestureRecognizer(this,
DnDConstants.ACTION_COPY,
dgl);
public Class getCompClass()
return compClass;
}Oh and here is ObjectFactory which simply instantiates Objects of a given class and sets their text to their classname (very crudely)...public class ObjectFactory
public static Object instantiate(Class objectClass)
Object o = null;
try
o = objectClass.newInstance();
catch (Exception e)
System.out.println("ObjectFactory#instantiate: " + e);
String name = objectClass.getName();
int lastDot = name.lastIndexOf('.');
name = name.substring(lastDot + 1);
if (o instanceof JLabel)
((JLabel)o).setText(name);
if (o instanceof JButton)
((JButton)o).setText(name);
if (o instanceof JTextComponent)
((JTextComponent)o).setText(name);
return o;
}Two more classes required by this codepublic class ObjectTransferHandler extends TransferHandler {
private static DataFlavor df;
* Constructor for ObjectTransferHandler.
public ObjectTransferHandler() {
super();
try {
df = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType);
} catch (ClassNotFoundException e) {
Debug.trace(e.toString());
public Transferable createTransferable(JComponent jC) {
Transferable t = null;
try {
t = new ObjectTransferable(((Dragable) jC).getCompClass());
} catch (Exception e) {
Debug.trace(e.toString());
return t;
public int getSourceActions(JComponent c) {
return DnDConstants.ACTION_MOVE;
public boolean canImport(JComponent comp, DataFlavor[] flavors) {
if (!(comp instanceof Dragable) && flavors[0].equals(df))
return true;
return false;
public boolean importData(JComponent comp, Transferable t) {
JComponent c = null;
try {
c = (JComponent) t.getTransferData(df);
} catch (Exception e) {
Debug.trace(e.toString());
comp.add(c);
comp.validate();
return true;
public class ObjectTransferable implements Transferable {
private static DataFlavor df = null;
private Class objectClass;
ObjectTransferable(Class objectClass) {
try {
df = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType);
} catch (ClassNotFoundException e) {
System.out.println("ObjectTransferable: " + e);
this.objectClass = objectClass;
* @see java.awt.datatransfer.Transferable#getTransferDataFlavors()
public DataFlavor[] getTransferDataFlavors() {
return new DataFlavor[] { df };
* @see java.awt.datatransfer.Transferable#isDataFlavorSupported(DataFlavor)
public boolean isDataFlavorSupported(DataFlavor testDF) {
return testDF.equals(df);
* @see java.awt.datatransfer.Transferable#getTransferData(DataFlavor)
public Object getTransferData(DataFlavor arg0)
throws UnsupportedFlavorException, IOException {
return ObjectFactory.instantiate(objectClass);
}And of course the test class:public class DragAndDropTest extends JFrame
JPanel leftPanel = new JPanel();
JPanel rightPanel = new JPanel();
Container contentPane = getContentPane();
Dragable dragableJLabel;
Dragable dragableJButton;
Dragable dragableJTextField;
Dragable dragableJTextArea;
* Constructor DragAndDropTest.
* @param title
public DragAndDropTest(String title)
super(title);
dragableJLabel = new Dragable(JLabel.class);
dragableJButton = new Dragable(JButton.class);
dragableJTextField = new Dragable(JTextField.class);
dragableJTextArea = new Dragable(JTextArea.class);
leftPanel.setBorder(new EtchedBorder());
BoxLayout boxLay = new BoxLayout(leftPanel, BoxLayout.Y_AXIS);
leftPanel.setLayout(boxLay);
leftPanel.add(dragableJLabel);
leftPanel.add(dragableJButton);
leftPanel.add(dragableJTextField);
leftPanel.add(dragableJTextArea);
rightPanel.setPreferredSize(new Dimension(500,500));
rightPanel.setBorder(new EtchedBorder());
rightPanel.setTransferHandler(new ObjectTransferHandler());
contentPane.setLayout(new BorderLayout());
contentPane.add(leftPanel, "West");
contentPane.add(rightPanel, "Center");
public static void main(String[] args)
JFrame frame = new DragAndDropTest("Drag and Drop Test");
frame.pack();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
}I wrote this code some time ago, so it won't be perfect but hopefully will give you some good ideas.
Regards,
Tim -
Need help with a simple program (should be simple anyway)
I'm (starting to begin) writing a nice simple program that should be easy however I'm stuck on how to make the "New" button in the file menu clear all the fields. Any help? I'll attach the code below.
====================================================
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Message extends JFrame implements ActionListener {
public void actionPerformed(ActionEvent evt) {
text1.setText(" ");
text2.setText("RE: ");
text3.setText(" ");
public Message() {
super("Write a Message - by Kieran Hannigan");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(370,270);
FlowLayout flo = new FlowLayout(FlowLayout.RIGHT);
setLayout(flo);
//Make the bar
JMenuBar bar = new JMenuBar();
//Make "File" on Menu
JMenu File = new JMenu("File");
JMenuItem f1 = new JMenuItem("New");f1.addActionListener(this);
JMenuItem f2 = new JMenuItem("Open");
JMenuItem f3 = new JMenuItem("Save");
JMenuItem f4 = new JMenuItem("Save As");
JMenuItem f5 = new JMenuItem("Exit");
File.add(f1);
File.add(f2);
File.add(f3);
File.add(f4);
File.add(f5);
bar.add(File);
//Make "Edit" on menu
JMenu Edit = new JMenu("Edit");
JMenuItem e1 = new JMenuItem("Cut");
JMenuItem e2 = new JMenuItem("Paste");
JMenuItem e3 = new JMenuItem("Copy");
JMenuItem e4 = new JMenuItem("Repeat");
JMenuItem e5 = new JMenuItem("Undo");
Edit.add(e5);
Edit.add(e4);
Edit.add(e1);
Edit.add(e3);
Edit.add(e2);
bar.add(Edit);
//Make "View" on menu
JMenu View = new JMenu("View");
JMenuItem v1 = new JMenuItem("Bold");
JMenuItem v2 = new JMenuItem("Italic");
JMenuItem v3 = new JMenuItem("Normal");
JMenuItem v4 = new JMenuItem("Bold-Italic");
View.add(v1);
View.add(v2);
View.add(v3);
View.addSeparator();
View.add(v4);
bar.add(View);
//Make "Help" on menu
JMenu Help = new JMenu("Help");
JMenuItem h1 = new JMenuItem("Help Online");
JMenuItem h2 = new JMenuItem("E-mail Programmer");
Help.add(h1);
Help.add(h2);
bar.add(Help);
setJMenuBar(bar);
//Make Contents of window.
//Make "Subject" text field
JPanel row2 = new JPanel();
JLabel sublabel = new JLabel("Subject:");
row2.add(sublabel);
JTextField text2 = new JTextField("RE:",24);
row2.add(text2);
//Make "To" text field
JPanel row1 = new JPanel();
JLabel tolabel = new JLabel("To:");
row1.add(tolabel);
JTextField text1 = new JTextField(24);
row1.add(text1);
//Make "Message" text area
JPanel row3 = new JPanel();
JLabel Meslabel = new JLabel("Message:");
row3.add(Meslabel);
JTextArea text3 = new JTextArea(6,22);
messagearea.setLineWrap(true);
messagearea.setWrapStyleWord(true);
JScrollPane scroll = new JScrollPane(text3,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
//SpaceLine
JPanel spaceline = new JPanel();
JLabel spacer = new JLabel(" ");
spaceline.add(spacer);
row3.add(scroll);
add(row1);
add(row2);
add(spaceline);
add(spaceline);
add(row3);
setVisible(true);
public static void main(String[] arguments) {
Message Message = new Message();
}persiandude wrote:
Topic: Need help with if, else, and which statements and loops.
How would I display 60 < temp. <= 85 in java
System.out.println("60 < temp. <= 85 in java");
another question is how do I ask a question like want to try again (y/n) after a output and asking that everytime I type in yes after a output and terminate when saying No.Sun's [basic Java tutorial|http://java.sun.com/docs/books/tutorial/]
Sun's [New To Java Center|http://java.sun.com/learning/new2java/index.html].Includes an overview of what Java is, instructions for setting up Java, an intro to programming (that includes links to the above tutorial or to parts of it), quizzes, a list of resources, and info on certification and courses.
[http://javaalmanac.com|http://javaalmanac.com]. A couple dozen code examples that supplement [The Java Developers Almanac|http://www.amazon.com/exec/obidos/tg/detail/-/0201752808?v=glance].
jGuru. A general Java resource site. Includes FAQs, forums, courses, more.
JavaRanch. To quote the tagline on their homepage: "a friendly place for Java greenhorns." FAQs, forums (moderated, I believe), sample code, all kinds of goodies for newbies. From what I've heard, they live up to the "friendly" claim.
Bruce Eckel's [Thinking in Java|http://mindview.net/Books/DownloadSites] (Available online.)
Joshua Bloch's [Effective Java|http://www.amazon.com/Effective-Java-2nd-Joshua-Bloch/dp/0321356683/ref=pd_bbs_1?ie=UTF8&s=books&qid=1214349768&sr=8-1]
Bert Bates and Kathy Sierra's [Head First Java|http://www.amazon.com/exec/obidos/tg/detail/-/0596004656?v=glance].
James Gosling's [The Java Programming Language|http://www.bookpool.com/sm/0321349806]. -
Need help with accessing the program.
I need help with accessing my adobe creative cloud on my windows 8.1 laptop. I have an account but do not have an app. I need this for my online classes. Please help!
Link for Download & Install & Setup & Activation may help
-Chat http://www.adobe.com/support/download-install/supportinfo/ -
Plz need help with this hashmap program
as far as i know, this hashmap program works, but i cant get it to compile correctly because of one line error:
phoneArray[2] = int f;
the second position in phoneArray is and will always be a number, but the array is a String array, making it difficult for me to take the number in that position and change it.
In actuality, the number is a score (a grade) and i need to take it to change it to a letter grade, where it will later be spit out in order from Name, Year, Score, Grade.
plz help, this is a school assignment and its driving me mad.
import java.util.*;
import java.io.*;
* A class that represents a phone book. This phone
* book maps names to phone numbers. This will
* read teh phone book information from a file.
public class CourseData2 {
/////////////////// fields ///////////////////
private String fileName;
private Map phoneMap = new HashMap();
/////////////////// constructors ///////////////////
* Constructor that takes a file name and reads
* in the names and phone numbers from a file.
* @param file the name of the file to read
public CourseData2(String file) {
this.fileName = file;
// Read the map information in form the file
readInfoFromFile();
} // constructor
/////////////////// methods ///////////////////
* Get the phone number for hte passed nam
* @param name the name to look up in hte map
* @return the phone number if found, else null
public String getPhoneNumber(String name) {
String phoneNumber = (String) phoneMap.get(name);
return phoneNumber;
} // method getPhoneNumber()
* Method to read the phone information from a
* file and use it to fill hte map
public void readInfoFromFile() {
String line = null;
String[] phoneArray = null;
try {
// create the reader
BufferedReader reader =
new BufferedReader(new FileReader(fileName));
// loop reading from the file
while ((line = reader.readLine()) != null) {
if (line.indexOf(":") >= 0) {
phoneArray = line.split(":");
phoneMap.put(phoneArray[0].trim(),
phoneArray[1].trim(),
phoneArray[2].trim());
} // if
} // while
(int)phoneArray[2] = int f;
if (f < 60) { (String)a = "E";}
else if (60 <= f < 70) { (String)f = "D";}
else if (70 <= f < 80) { (String)f = "C";}
else if (70 <= f < 90) { (String)f = "B";}
else if (90 <= f) { (String)a = "A";}
// Close the reader
reader.close();
} // try
catch (FileNotFoundException ex) {
SimpleOutput.showError("Could not find the file \"" + fileName + "\".");
} // catch
catch (Exception ex) {
ex.printStackTrace();
} // catch
} // method readInfoFromFile()
public void printBook() {
// Sort hashtable.
Vector phoneVector = new Vector(phoneMap.keySet());
Collections.sort(phoneVector);
// Display (sorted) hashtable.
for (Enumeration phoneEnumeration = phoneVector.elements(); phoneEnumeration.hasMoreElements();) {
String key = (String)phoneEnumeration.nextElement();
System.out.println("Name: " + key + ", Year: " + phoneMap.get(key) + ", Score: " + phoneMap.get(key) + ", Grade: " + phoneMap.get(key));
} // for
} // method printBook()
/* main method for testing */
public static void main(String[] args) {
CourseData2 phoneBook = new CourseData2("scores12.txt");
System.out.println(phoneBook.getPhoneNumber("Lee"));
System.out.println(phoneBook.getPhoneNumber("Smith"));
phoneBook.printBook();
} // main()
} // classafter much time and editing, this is the revised coding:
import java.util.*;
import java.io.*;
* A class that represents a class score book. This
* book maps names to scores and grades. This will
* read the names, scores and grade information from a file.
public class CourseData2 {
/////////////////// fields ///////////////////
private String fileName;
private Map phoneMap = new HashMap();
/////////////////// constructors ///////////////////
* Constructor that takes a file name and reads
* in the names and phone numbers from a file.
* @param file the name of the file to read
public CourseData2(String file) {
this.fileName = file;
// Read the map information in form the file
readInfoFromFile();
} // constructor
/////////////////// methods ///////////////////
* Get the phone number for hte passed nam
* @param name the name to look up in hte map
* @return the phone number if found, else null
public String getPhoneNumber(String name) {
String phoneNumber = (String) phoneMap.get(name);
return phoneNumber;
} // method getPhoneNumber()
* Method to read the phone information from a
* file and use it to fill hte map
public void readInfoFromFile() {
String line = null;
String[] phoneArray = null;
String a = "";
try {
// create the reader
BufferedReader reader =
new BufferedReader(new FileReader(fileName));
// loop reading from the file
while ((line = reader.readLine()) != null) {
while ((line = reader.readLine()) != null) {
if (line.indexOf(":") >= 0) {
phoneArray = line.split(":");
int f = Integer.parseInt(phoneArray[2]);
if (0 <= f && f <= 100) {
if (0 <= f && f < 60) { a = "E";}
else if (60 <= f && f < 70) { a = "D";}
else if (70 <= f && f < 80) { a = "C";}
else if (80 <= f && f < 90) { a = "B";}
else if (90 <= f && f <= 100) { a = "A";}
} // if f between 0 and 100
else if ( f > 100 && f < 0 ) {
SimpleOutput.showError("Score is not an integer");
String g = new String();
g = phoneArray[2];
}//if < 0
}// if (line.index....
phoneMap.put(phoneArray[0].trim(),
(phoneArray[1].trim() + phoneArray[2].trim() + (String)a));
} // while2
} // while
// Close the reader
reader.close();
} // try
catch (FileNotFoundException ex) {
SimpleOutput.showError("Could not find the file \"" + fileName + "\".");
} // catch
catch (Exception ex) {
ex.printStackTrace();
} // catch
} // method readInfoFromFile()
public void printBook() {
// Sort hashtable.
Vector phoneVector = new Vector(phoneMap.keySet());
Collections.sort(phoneVector);
// Display (sorted) hashtable.
for (Enumeration phoneEnumeration = phoneVector.elements(); phoneEnumeration.hasMoreElements();) {
String key = (String)phoneEnumeration.nextElement();
System.out.println("Name: " + key + ", Year: " + phoneMap.get(key) + ", Score: " + phoneMap.get(key) + ", Grade: " + phoneMap.get(key));
} // for
} // method printBook()
/* main method for testing */
public static void main(String[] args) {
CourseData2 phoneBook = new CourseData2("scores12.txt");
System.out.println(phoneBook.getPhoneNumber("Depp"));
System.out.println(phoneBook.getPhoneNumber("Gonzales"));
System.out.println(phoneBook.getPhoneNumber("Jenkins"));
System.out.println(phoneBook.getPhoneNumber("Lee"));
System.out.println(phoneBook.getPhoneNumber("Mac Donald"));
System.out.println(phoneBook.getPhoneNumber("O'Malley"));
System.out.println(phoneBook.getPhoneNumber("Price"));
System.out.println(phoneBook.getPhoneNumber("Ramesh"));
System.out.println(phoneBook.getPhoneNumber("Smith"));
System.out.println(phoneBook.getPhoneNumber("Winston"));
phoneBook.printBook();
} // main()
} // classthis has no errors, but gives me 4 warnings, which i can't solve, plz help -
Need Help with simple array program!
Hi, I have just recently started how to use arrays[] in Java and I'm a bit confused and need help designing a program.
What this program does, it reads in a range of letters specified by the user. The user then enters the letters (a, b or c) and stores these characters into an array, which the array's length is equal to the input range the user would enter at the start of the program. The program is then meant to find how many times (a,b and c) appears in the array and the Index it first appears at, then prints these results.
Here is my Code for the program, hopefully this would make sense of what my program is suppose to do.
import B102.*;
class Letters
static int GetSize()
int size = 0;
boolean err = true;
while(err == true)
Screen.out.println("How Many Letters would you like to read in?");
size = Keybd.in.readInt();
err = Keybd.in.fail();
Keybd.in.clearError();
if(size <= 0)
err = true;
Screen.out.println("Invalid Input");
return(size);
static char[] ReadInput(int size)
char input;
char[] letter = new char[size];
for(int start = 1; start <= size; start++)
System.out.println("Please enter a letter (a, b or c) ("+size+" max), enter # to stop:");
input = Keybd.in.readChar();
while((input != 'a') && (input != 'b') && (input != 'c') && (input != '#'))
Screen.out.println("Invalid Input");
System.out.println("Please enter a letter (a, b or c) ("+size+" max, enter # to stop:");
input = Keybd.in.readChar();
while(input == '#')
start == size;
break;
for(int i = 0; i < letter.length; i++)
letter[i] = input;
return(letter);
static int CountA(char[] letter)
int acount = 0;
for(int i = 0; i < letter.length; i++)
if(letter[i] == 'a')
acount++;
return(acount);
static int CountB(char[] letter)
int bcount = 0;
for(int i = 0; i < letter.length; i++)
if(letter[i] == 'b')
bcount++;
return(bcount);
static int CountC(char[] letter)
int ccount = 0;
for(int i = 0; i < letter.length; i++)
if(letter[i] == 'c')
ccount++;
return(ccount);
static int SearchA(char[] letter)
int ia;
for(ia = 0; ia < letter.length; ia++)
if(letter[ia] == 'a')
return(ia);
return(ia);
static int SearchB(char[] letter)
int ib;
for(ib = 0; ib < letter.length; ib++)
if(letter[ib] == 'b')
return(ib);
return(ib);
static int SearchC(char[] letter)
int ic;
for(ic = 0; ic < letter.length; ic++)
if(letter[ic] == 'c')
return(ic);
return(ic);
static void PrintResult(char[] letter, int acount, int bcount, int ccount, int ia, int ib, int ic)
if(ia <= 1)
System.out.println("There are "+acount+" a's found, first appearing at index "+ia);
else
System.out.println("There are no a's found");
if(ib <= 1)
System.out.println("There are "+bcount+" b's found, first appearing at index "+ib);
else
System.out.println("There are no b's found");
if(ic <= 1)
System.out.println("There are "+ccount+" c's found, first appearing at index "+ic);
else
System.out.println("There are no c's found");
return;
public static void main(String args[])
int size;
char[] letter;
int acount;
int bcount;
int ccount;
int ia;
int ib;
int ic;
size = GetSize();
letter = ReadInput(size);
acount = CountA(letter);
bcount = CountB(letter);
ccount = CountC(letter);
ia = SearchA(letter);
ib = SearchB(letter);
ic = SearchC(letter);
PrintResult(letter, acount, bcount, ccount, ia, ib, ic);
return;
} Some errors i get with my program are:
When reading in the letters to store into the array, I get the last letter I entered placed into the entire array. Also I believe my code to find the Index is incorrect.
Example Testing: How many letters would you like to read? 3
Enter letter (a, b or c) (# to quit): a
Enter letter (a, b or c) (# to quit): b
Enter letter (a, b or c) (# to quit): c
It prints "There are no a's'" (there should be 1 a at index 0)
"There are no b's" (there should be 1 b at index 1)
and "There are 3 c's, first appearing at index 0" ( there should be 1 c at index 2)
The last thing is that my code for when the user enters "#" that the input of letters would stop and the program would then continue over to the counting and searching part for the letters, my I believe is correct but I get the same problem as stated above where the program takes the character "#" and stores it into the entire array.
Example Testing:How many letters would you like to read? 3
Enter letter (a, b or c) (# to quit): a
Enter letter (a, b or c) (# to quit): #
It prints "There are no a's'" (should have been 1 a at index 0)
"There are no b's"
and "There are no c's"
Can someone please help me??? or does anyone have a program simular to this they have done and would'nt mind showing me how it works?
Thanks
lou87.Without thinking too much...something like this
for(int start = 0; start < size; start++) {
System.out.println("Please enter a letter (a, b or c) ("+size+" max), enter # to stop:");
input = Keybd.in.readChar();
while((input != 'a') && (input != 'b') && (input != 'c') && (input != '#')) {
Screen.out.println("Invalid Input");
System.out.println("Please enter a letter (a, b or c) ("+size+" max, enter # to stop:");
input = Keybd.in.readChar();
if(input == '#') {
break;
letter[start] = input;
}you dont even need to do start = size; coz with the break you go out of the for loop. -
Hello. I'm posting in these forums because I really don't know where else to go. I have been trying for the past several days to figure out how to go about writing my program but to no avail. The project requires reading many lines each containing several different elements from a datafile named "DATA". A few examples of some lines from that file:
Department number/Number of units received/Date on which the shipment arrived/Expiration date/Name of Object
0 78 02/03/2001 02/12/2001 apples
0 26 06/03/2001 06/10/2001 lemons
3 62 03/06/2001 03/14/2001 hamburger
What we have to do with this data is read all of it from the file, separate all the different elements, and based on input from the user, sort everything and print it out to the screen. If the user enters 03, the program will show everything that arrived and expired within the month of March, sorted by date.
It is a pretty basic program, but my problem is that I have no idea how to go about reading in this data, putting it into a vector (probably the easiest method) or separating the different elements. I've gone to websites and looked through my textbooks but they didn't help much. If anyone has any resources that could help for writing such a program, or if anyone could offer help in writing the program, I would really appreciate it. I can also show what I've managed to write so far, or more details on how the program should work. Thanks in advance.
Mattsince im not a pro like some of the guys on here :),
and believe me thiers people here, who could write your whole app in a hour.
anyways my advice , would be to do a search on the forums for useing.bufferReader()
i think you would need to read the file in with bufferreader then split up each line useing the stringTokenizer and then use some algorithm to compare
the values and split them up into your vector arrays as needed.
thier is also fileinputStream i think you can use that too. -
Need help with spell checker program
Hi
I am writing a spell checker program and need help for a simple logic.I have "List" of correctly spelled words and a String array of wrong spelled words.How can I compare both and tell that for eg xyz word is not spelled correctly.BigDaddyLoveHandles wrote:
To learn more about Map, take the collection tutorial: [http://java.sun.com/docs/books/tutorial/collections/index.html]
(Actually, to me it sounds like you have a Set of correctly spelled words and another Set of words which may or may not be correctly spelled, and you want the difference...)That is what it sounds like to me also, and that is easy.
JSG -
Hi all ..
i am a new in Java and i need some help with my School Project ,,,
Will you help me ??
regards,
TootaPeople here will answer questions and comment on your code, but don't ecpect them to debug your source nor do your homework for you.
-
I'm a complete novice with Java. I want to write a Java program to run on Windows 2000 servers to write a list of certain files in a directory into a *.txt file. I hope to add complexity once I have this basic part working. Here's the code I have so far:
//this Java application finds poll* files
public class FindPollApp
//Create File Object
File dir = new File("d:/jda/windss/poll");
//List directory
if(dir.isDirectory())
String[] dirContents = dir.list();
for (int i=0; i < dirContents.length; i++)
System.out.println(dirContents);
//Iterate through files
I get the following errors:
C:\JAVA>javac FindPollApp.java
FindPollApp.java:9: illegal start of type
if(dir.isDirectory())
^
FindPollApp.java:18: <identifier> expected
^
2 errors
Thanks.I'm a complete novice with Java. I want to write a
Java program to run on Windows 2000 servers to write
a list of certain files in a directory into a *.txt
file. I hope to add complexity once I have this
basic part working. Here's the code I have so far:
//this Java application finds poll* files
public class FindPollApp
//Create File Object
File dir = new File("d:/jda/windss/poll");
//List directory
if(dir.isDirectory())
String[] dirContents = dir.list();
for (int i=0; i < dirContents.length; i++)
System.out.println(dirContents);
//Iterate through files
I get the following errors:
C:\JAVA>javac FindPollApp.java
FindPollApp.java:9: illegal start of type
if(dir.isDirectory())
^
FindPollApp.java:18: <identifier> expected
^
2 errors
Thanks.
You need to create a method and insert your if statement in there
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