I am a beginner at Java.
I have been given an assignment to make a simple address book(without applets) using Java.
It should have the following functions:-
1) search-by name,city.
2)add-name,telephone number,city,address.
3)modify.
4)delete.

I am still working on the program.But the problem comes when the screen(black one) becomes too crowded(main menu has to be repeated to ask the user what to do next).

So is there any function to clear the screen before?

Please inform me about it as soon as possible.
Thank you,
Shubhang.

Hi Shubhang and welcome to DaniWeb :)

I am sorry, but I don't understand what you are asking. Can you please post some code to show us what you mean?

Hi Shubhang and welcome to DaniWeb :)

I am sorry, but I don't understand what you are asking. Can you please post some code to show us what you mean?

I think he is saying that when the application is running, in DOS for example, the window becomes too crowded with all the System.out.println messages. So he would like a way to "clear" the command window from the messages.

But I don't know if there is a way to do it purely with java. Of course there are DOS and UNIX commands that do that, so IF there isn't another way, you might want to try and calling those from your program. But this I think will get a little more complicated than that you actually wanted.

Of course if there is another way feel free to correct me.

I think he is saying that when the application is running, in DOS for example, the window becomes too crowded with all the System.out.println messages. So he would like a way to "clear" the command window from the messages.

But I don't know if there is a way to do it purely with java. Of course there are DOS and UNIX commands that do that, so IF there isn't another way, you might want to try and calling those from your program. But this I think will get a little more complicated than that you actually wanted.

Of course if there is another way feel free to correct me.

In the program, I display the main menu,then ask for user's choice.
after the task is performed I display the main menu again to ask for what should be done next.

Each time the task is over it stays on the window and crowds it.
Is there any function or way to clear the command window before repeating the display of the main menu?

clearing... not that I know of, but you can make a print of, for instance, thirty empty lines. this way, it 'll look as if the screen has been cleared. you might not have your menu on top of the screen every time though :)

Actually I just thought of a VERY DUMP way to do it. It is not smart from programming terms.
I have already told you a way that might be done (running the appropriate DOS command using java) but if it is too difficult you can always try this:

for (int i=0;i<100;i++) {
  System.out.println();
}

It doesn't do what you want but it will look like it

I am doing the same thing, but I need to know how to do the following:

Allow for editing

and

Allow for searching by state or by any other options

This is what I have so far:

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

public class AddressBook extends JFrame {
  // Specify the size of five string fields in the record
  final static int NAME_SIZE = 32;
  final static int STREET_SIZE = 32;
  final static int CITY_SIZE = 20;
  final static int STATE_SIZE = 2;
  final static int ZIP_SIZE = 5;
// added record number
  final static int RECORDNUM_SIZE = 5;
  final static int RECORD_SIZE =
    (NAME_SIZE + STREET_SIZE + CITY_SIZE + STATE_SIZE + RECORDNUM_SIZE + ZIP_SIZE);

  // Access address.dat using RandomAccessFile
  private RandomAccessFile raf;

  // Text fields
  private JTextField jtfName = new JTextField(NAME_SIZE);
  private JTextField jtfStreet = new JTextField(STREET_SIZE);
  private JTextField jtfCity = new JTextField(CITY_SIZE);
  private JTextField jtfState = new JTextField(ZIP_SIZE);
  private JTextField jtfZip = new JTextField(ZIP_SIZE);
  private JTextField jtfRecordNum = new JTextField(RECORDNUM_SIZE);

  // Buttons
  private JButton jbtAdd = new JButton("Add");
  private JButton jbtFirst = new JButton("First");
  private JButton jbtNext = new JButton("Next");
  private JButton jbtPrevious = new JButton("Previous");
  private JButton jbtLast = new JButton("Last");
//edit button added
  private JButton jbtEdit = new JButton("Edit");

  public AddressBook() {
    // Open or create a random access file
    try {
      raf = new RandomAccessFile("address.dat", "rw");
    }
    catch(IOException ex) {
      System.out.print("Error: " + ex);
      System.exit(0);
    }

    // Panel p1 for holding labels Name, Street, and City
    JPanel p1 = new JPanel();
    p1.setLayout(new GridLayout(5, 1));
    p1.add(new JLabel("Name"));
    p1.add(new JLabel("Street"));
    p1.add(new JLabel("City"));
// Record Number Label Holder
    p1.add(new JLabel("Record Number"));
    p1.add(new JLabel("Search: "));

    // Panel jpState for holding state
    JPanel jpState = new JPanel();
    jpState.setLayout(new BorderLayout());
    jpState.add(new JLabel("State"), BorderLayout.WEST);
    jpState.add(jtfState, BorderLayout.CENTER);

    // Panel jpZip for holding zip
    JPanel jpZip = new JPanel();
    jpZip.setLayout(new BorderLayout());
    jpZip.add(new JLabel("Zip"), BorderLayout.WEST);
    jpZip.add(jtfZip, BorderLayout.CENTER);

    // Panel p2 for holding jpState and jpZip
    JPanel p2 = new JPanel();
    p2.setLayout(new BorderLayout());
    p2.add(jpState, BorderLayout.WEST);
    p2.add(jpZip, BorderLayout.CENTER);

    // Panel p3 for holding jtfCity and p2
    JPanel p3 = new JPanel();
    p3.setLayout(new BorderLayout());
    p3.add(jtfCity, BorderLayout.CENTER);
    p3.add(p2, BorderLayout.EAST);

    // Panel p4 for holding jtfName, jtfStreet, and p3
    JPanel p4 = new JPanel();
    p4.setLayout(new GridLayout(3, 1));
    p4.add(jtfName);
    p4.add(jtfStreet);
    p4.add(p3);

    // Place p1 and p4 into jpAddress
    JPanel jpAddress = new JPanel(new BorderLayout());
    jpAddress.add(p1, BorderLayout.WEST);
    jpAddress.add(p4, BorderLayout.CENTER);

    // Set the panel with line border
    jpAddress.setBorder(new BevelBorder(BevelBorder.RAISED));

    // Add buttons to a panel
    JPanel jpButton = new JPanel();
    jpButton.add(jbtAdd);
    jpButton.add(jbtFirst);
    jpButton.add(jbtNext);
    jpButton.add(jbtPrevious);
    jpButton.add(jbtLast);
  // added
    jpButton.add(jbtEdit);

    // Add jpAddress and jpButton to the frame
    add(jpAddress, BorderLayout.CENTER);
    add(jpButton, BorderLayout.SOUTH);

    jbtAdd.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
		String s;
		s = jtfName.getText();
        if (s.length() != 0) {
			writeAddress();
			jtfName.setText("");
			jtfStreet.setText("");
			jtfCity.setText("");
			jtfState.setText("");
            jtfZip.setText("");
     //added
            jtfRecordNum.setText("");

		}
      }
    });
    jbtFirst.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          if (raf.length() > 0) readAddress(0);
        }
        catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    });
    jbtNext.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          long currentPosition = raf.getFilePointer();
          if (currentPosition < raf.length())
            readAddress(currentPosition);
        }
        catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    });
    jbtPrevious.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          long currentPosition = raf.getFilePointer();
          if (currentPosition - 2 * RECORD_SIZE > 0)
            // Why 2 * 2 * RECORD_SIZE? See the follow-up remarks
            readAddress(currentPosition - 2 * 2 * RECORD_SIZE);
          else
            readAddress(0);
        }
        catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    });
    jbtLast.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          long lastPosition = raf.length();
          if (lastPosition > 0)
            // Why 2 * RECORD_SIZE? See the follow-up remarks
            readAddress(lastPosition - 2 * RECORD_SIZE);
        }
        catch (IOException ex) {
          ex.printStackTrace();
        }
      }
    });

    // Display the first record if exists
    try {
      if (raf.length() > 0) readAddress(0);
    }
    catch (IOException ex) {
      ex.printStackTrace();
    }
  }

  /** Write a record at the end of the file */
  public void writeAddress() {
    try {
      raf.seek(raf.length());
      FixedLengthStringIO.writeFixedLengthString(
        jtfName.getText(), NAME_SIZE, raf);
      FixedLengthStringIO.writeFixedLengthString(
        jtfStreet.getText(), STREET_SIZE, raf);
      FixedLengthStringIO.writeFixedLengthString(
        jtfCity.getText(), CITY_SIZE, raf);
      FixedLengthStringIO.writeFixedLengthString(
        jtfState.getText(), STATE_SIZE, raf);
      FixedLengthStringIO.writeFixedLengthString(
        jtfZip.getText(), ZIP_SIZE, raf);
      //added
      FixedLengthStringIO.writeFixedLengthString(
        jtfZip.getText(), RECORDNUM_SIZE, raf);
    }
    catch (IOException ex) {
      ex.printStackTrace();
    }
  }

  /** Read a record at the specified position */
  public void readAddress(long position) throws IOException {
    raf.seek(position);
    String name = FixedLengthStringIO.readFixedLengthString(
      NAME_SIZE, raf);
    String street = FixedLengthStringIO.readFixedLengthString(
      STREET_SIZE, raf);
    String city = FixedLengthStringIO.readFixedLengthString(
      CITY_SIZE, raf);
    String state = FixedLengthStringIO.readFixedLengthString(
      STATE_SIZE, raf);
    String zip = FixedLengthStringIO.readFixedLengthString(
      ZIP_SIZE, raf);

    jtfName.setText(name);
    jtfStreet.setText(street);
    jtfCity.setText(city);
    jtfState.setText(state);
    jtfZip.setText(zip);
  }

  public static void main(String[] args) {
    AddressBook frame = new AddressBook();
    frame.pack();
    frame.setTitle("AddressBook");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}
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