newbie in java_help

[ghostrider_gr]

hello.. i am new to java..
what i want to do is read a series of datas. f.e read:
1234 4 5
2345 5 6
2345 6 7
and so on..
i do not know how many lines of data i will have so i am thinking that i will no use an array.. i am thinking of using something like a list but i haven't understood how do they work..

first of all i have this class:
class data{
int x;
int y;
int z;
}..

can anyone help me and give me the body of my code..??
how after reading those datas i will pute them in the list, how i will define the list, and then how i am going to pass through them??
thanks..

i ve done this:

Arraylist box=new arraylist();

while (condition for reading) {
data.x=...
data.y=...
data.z=...
box.add(data);
}
which is not correct...
what i want is "store them" as a package..

[Saman]

It is not goot to get your homework done by someone else. Instead study about Link List data structure. Following video might help you.



Here is one good implementation of Link Lists. Do not copy it. Just study it and write something by your own.

Code: Select all

/*
* Copyright (c) 2000 David Flanagan.  All rights reserved.
* This code is from the book Java Examples in a Nutshell, 2nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book (recommended),
* visit http://www.davidflanagan.com/javaexamples2.
*/

/**
* This class implements a linked list that can contain any type of object that
* implements the nested Linkable interface. Note that the methods are all
* synchronized, so that it can safely be used by multiple threads at the same
* time.
*/
public class LinkedList {
  /**
   * This interface defines the methods required by any object that can be
   * linked into a linked list.
   */
  public interface Linkable {
    public Linkable getNext(); // Returns the next element in the list

    public void setNext(Linkable node); // Sets the next element in the list
  }

  // This class has a default constructor: public LinkedList() {}

  /** This is the only field of the class. It holds the head of the list */
  Linkable head;

  /** Return the first node in the list */
  public synchronized Linkable getHead() {
    return head;
  }

  /** Insert a node at the beginning of the list */
  public synchronized void insertAtHead(Linkable node) {
    node.setNext(head);
    head = node;
  }

  /** Insert a node at the end of the list */
  public synchronized void insertAtTail(Linkable node) {
    if (head == null)
      head = node;
    else {
      Linkable p, q;
      for (p = head; (q = p.getNext()) != null; p = q)
        /* no body */;
      p.setNext(node);
    }
  }

  /** Remove and return the node at the head of the list */
  public synchronized Linkable removeFromHead() {
    Linkable node = head;
    if (node != null) {
      head = node.getNext();
      node.setNext(null);
    }
    return node;
  }

  /** Remove and return the node at the end of the list */
  public synchronized Linkable removeFromTail() {
    if (head == null)
      return null;
    Linkable p = head, q = null, next = head.getNext();
    if (next == null) {
      head = null;
      return p;
    }
    while ((next = p.getNext()) != null) {
      q = p;
      p = next;
    }
    q.setNext(null);
    return p;
  }

  /**
   * Remove a node matching the specified node from the list. Use equals()
   * instead of == to test for a matched node.
   */
  public synchronized void remove(Linkable node) {
    if (head == null)
      return;
    if (node.equals(head)) {
      head = head.getNext();
      return;
    }
    Linkable p = head, q = null;
    while ((q = p.getNext()) != null) {
      if (node.equals(q)) {
        p.setNext(q.getNext());
        return;
      }
      p = q;
    }
  }

  /**
   * This is a test class that implements the Linkable interface
   */
  static class LinkableInteger implements Linkable {
    int i; // The data contained in the node

    Linkable next; // A reference to the next node in the list

    public LinkableInteger(int i) {
      this.i = i;
    } // Constructor

    public Linkable getNext() {
      return next;
    } // Part of Linkable

    public void setNext(Linkable node) {
      next = node;
    } // Linkable

    public String toString() {
      return i + "";
    } // For easy printing

    public boolean equals(Object o) { // For comparison
      if (this == o)
        return true;
      if (!(o instanceof LinkableInteger))
        return false;
      if (((LinkableInteger) o).i == this.i)
        return true;
      return false;
    }
  }

  /**
   * The test program. Insert some nodes, remove some nodes, then print
   * out all elements in the list. It should print out the numbers 4, 6,
   * 3, 1, and 5
   */
  public static void main(String[] args) {
    LinkedList ll = new LinkedList(); // Create a list
    ll.insertAtHead(new LinkableInteger(1)); // Insert some stuff
    ll.insertAtHead(new LinkableInteger(2));
    ll.insertAtHead(new LinkableInteger(3));
    ll.insertAtHead(new LinkableInteger(4));
    ll.insertAtTail(new LinkableInteger(5));
    ll.insertAtTail(new LinkableInteger(6));
    System.out.println(ll.removeFromHead()); // Remove and print a node
    System.out.println(ll.removeFromTail()); // Remove and print again
    ll.remove(new LinkableInteger(2)); // Remove another one

    // Now print out the contents of the list.
    for (Linkable l = ll.getHead(); l != null; l = l.getNext())
      System.out.println(l);
  }

}