Linked Lists, Hashing, and sore heads.

I am working with a team on a java program as part of an algorithms assignment. We have completed the program however I'm convinced its not working. The program is supposed to carry out a defined number of searches, additionions and deletions to a linked list and time it. We have been supplied with a number of ext files with random numbers for testing purposes.
The text files are different sizes. We are finding that our results are the same regardless which file we use and which arguments are passed into the program. I would be greatful if someone could cast their eye over the work and let us know what you think.
All files are at
http://students.odl.qmul.ac.uk/~dm07/algorithms/.
IntSet.java is the program we have completed from a skeleton code.
Evaluator.java is the wrapper provided. data.zip is a full file of the
different test text files although there are two on here for quick download.
Any direction or feedback would be really appreciated.
Dermot.

Here is the result for the 50 random numbers text file :
D:\Coursework\Algorithms>java Evaluator size-50-random.txt 10000
Setting up, please wait ...
Finished setting up.
Start searches
It took 0.010 seconds for 10000 searches
It took 0.020 seconds for 10000 additions
It took 0.010 seconds for 10000 deletions
And here is the result for hte 50000 random numbers text file :
D:\Coursework\Algorithms>java Evaluator size-50000-random.txt 10000
Setting up, please wait ...
Finished setting up.
Start searches
It took 0.010 seconds for 10000 searches
It took 0.020 seconds for 10000 additions
It took 0.000 seconds for 10000 deletions
As you can see they are virtually identical. Even after running a number of times and working out averages they are the same. I thought that the results should be exponential but they are not. I understand that results should change from pc setup to pc setup, depending on processor etc but we are not getting this.
Dermot.

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OK -- I've had a cup and my systems are coming back on line...
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[email protected]

I'll try and point you in the right direction without being too explicit as you request.
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Hi jverd,
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THE ERROR HAPPENS HERE ON THIS LINE          list.insert(datum.name);
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Circular Linked List Help

Hi,
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You need a Node class and a class that manages the nodes. The class the manages the nodes is typically called something like MyLinkedList. The MyLinkedList class will typically have a member called 'head' or 'first' and another member called 'last', 'end', or 'tail'. Those members will contain references to the first node and the last node respectively.
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Message was edited by:
7stud

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Yeah, unfortunately, I had to design my own linked list for my assignment (that's taken almost 40+ hours). So, now every alogrithm I've tried to write seems to give me a null pointer, for example this one
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bump

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Edited by: klawson88 on Feb 12, 2009 12:32 AM

Anyone help me please~ many thanks! C++ linked list

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Too vague.
If you could show us some relevant Java and JNI C++
code.
Please paste your code between code tags exactly like
this:
your codeYou may read the [url
http://forum.java.sun.com/help.jspa?sec=formatting]For
matting tips for more information.Here you are:
this is the header definition of the linked list handler, all functions are set to be non-static
typedef struct DeviceLinkList{
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} DeviceLinkList;
class DeviceListHandler
public:
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void addNode(char *device); //add monitor device
void deleteNode(char *device); //remove after device is stop monitorred
void printAll();
void setResult(char *device);
private:
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void DeviceListHandler::addNode(char *device)
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Can you create a second, sorted linked list?The prof. didn't specify whether or not I can use a second list.
Are you prohibited from using the collections framework (probably, if it is a school assignment!)Not really sure on this one. Again it is not specified in the assignment
(Why would they have you store this data in a linked list??)I their reasoning is to have us learn how to implement linked list because it can grow or shrink when necessary.(Other than that I don't understand the practicality of it either)
Are you using a doubly linked list (forwards and backwards)?The assignment does not specify a certain linked list to use.
Did your prof mention any sort algorithms you might use? He states later in the assignment that I have to generate different growth reports by using MergeSort.
I appreciate your help and comments. Unfortunately my prof. is very vague about the assignment and its implementation in his outline. He just kind of throws us into it hoping that we will figure it out.

WPC - highlighting the link of the current page in the link list

Hi,
is there any way to highlight a link in my linklist if it's the link to the page i am currently visiting?
That would make it possible for me to customize the link list form and change it into some kind of "tab"-list form where the current tab is highlighted.
A solution via xsl would be fantastic.
Thanks for your support.
Sebastian

You can submit ideas here - http://hendrix.mozilla.org/
The [https://addons.mozilla.org/firefox/addon/3880/ Add Bookmark Here ²] extension does what you want.

Doubly Linked Lists

Hi there,
i have just started to use java and was on the topic of doubly linked list and am confused. Is it possible for someone to show me how to implement a doubly linked list????
Thanx

if i had to do it, then i'd make a class that's this linked list object, and another class that's node object.
in list object i'd hold count of nodes (in case someone asks that, so i should not go through list and count all those 1000000 nodes), and would also have reference to first and last node.
public class KstyleDLList {
KstyleNode first = null;
KstyleNode last = null;
private int count;
public int getCount() {
return count;
public void addNode(KstyleNode node) {
last.setNext(node); // simply ignore returned value
// because if everything is OK, then value returned is null
next = node;
public void removeNode(int index) {
// method body here
public KstyleNode getFirst() {
// method body here
public Kstyle getLast() {
// method body here
class KstyleNode {
private KstyleNode next = null;
private KstyleNode prev = null;
public KstyleNode setNext(KstyleNode next) {
KstyleNode old = this.next;
this.next = next;
return old;
public getNext() {
// method body here
public KstyleNode setPrev(KstyleNode prev) {
// method body here
public KstyleNode getPrev() {
// method body here
}and lots of other methods that i haven't implemented yet.. but this should give you some idea of what you're going to do...

How to Implement a Chained Hash Table with Linked Lists

I'm making a migration from C/C++ to Java, and my task is to implement a Chained Hash Table with a Linked List. My problem is to put the strings(in this case names) hashed by the table using de Division Metod (H(k)= k mod N) in to a Linked list that is handling the colisions. My table has an interface implemented(public boolean insert(), public boolean findItem(), public void remove()). Any Help is needed. Thanks for everyone in advance.

OK. you have your hash table. What you want it to do is keep key/value pairs in linked lists, so that when there is a collision, you add the key/value pair to the linked list rather than searching for free space on the table.
This means that whenever you add an item, you hash it out, check to see if there is already a linked list and if not, create one and put it in that slot. Then in either case you add the key/value pair to the linked list if the key is not already on the linked list. If it is there you have to decide whether your requirements are to give an error or allow duplicate keys or just keep or modify one or the other (old/new).
When you are searching for a key, you hash it out once again and check to see if there is a linked list at that slot. If there is one, look for the key and if it's there, return it and if not, or if there was no linked list at that slot, return an error.
You aren't clear on whether you can simply use the provided linked-list implementations in the Java Collections or whether you have to cobble the linked list yourself. In any case, it's up to you.
Is this what you're asking?
Doug

Linked Lists, Hashing, and sore heads.

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