Problems sorting custommade linkedlist

Question

Hi guys, I have a problem (obviously).
Its an assignment for school and I'm supposed to write my own LinkedList (called PhoneDirectory) instead of using the already defined one in java. After a fairly large amount of time I succeeded with that.
To get an A though I need to also create a subclass of the PhoneDirectory called SortedPhoneDirectory with the only difference that the insert method automatically places the new Person in the right place in the list based on name. I have now succeded with that as well, but something is wrong, which brings me to my problem:
When I access the methods in the PhoneDirectory class nothing happens - nothing at all. WHY :O:P
Here are all my classes
The class PhoneDirectory:
The class PhoneDirectory is a Linked List containing Person objects.
class PhoneDirectory
    private Node header;
    public PhoneDirectory()
        header = new Node(null );
    public void insert( Person o)
        header = new Node ( o, header);
    public void findWithName(String name)
        name = name.toLowerCase();
        Node runner = header;
        Person tmp;
        int i = 0;
        while(runner.element != null)
            tmp = get(i);
            if(tmp.getName().toLowerCase().contains(name))
                System.out.println(tmp);
            runner = runner.next;
            i++;
    public void findWithAdress(String adress)
        adress = adress.toLowerCase();
        Node runner = header;
        Person tmp;
        int i = 0;
        while(runner.element != null)
            tmp = get(i);
            if(tmp.getAdress().toLowerCase().contains(adress))
                System.out.println(tmp);
            runner = runner.next;
            i++;
    public void findWithPhone(String phone)
        phone = phone.toLowerCase();
        Node runner = header;
        Person tmp;
        int i = 0;
        while(runner.element != null)
            tmp = get(i);
            if(tmp.getPhoneNumber().toLowerCase().contains(phone))
                System.out.println(tmp);
            runner = runner.next;
            i++;
    public void remove(int val)
        if(header == null)
            System.out.println("Its empty!");
        else if(val == 0)
            header = header.next;
        else
            Node runner = null;
            Node previous = null;
            runner = header.next;
            previous = header;
            int i = 1;
            while(runner.element != null)
                if(i == val)
                    previous.next = runner.next;
                previous = runner;
                runner = runner.next;
                i++;
    public void removeFirst()
        if(header == null)
            System.out.println("Its empty!");
        else
            header = header.next;
    public void print()
        Node tmp = header;
        while(tmp.element != null)
            System.out.println(tmp.element);
            tmp = tmp.next;
    public Person get(int val)
        int i = 0;
        boolean abort = false;
        Node tmp = header;
        while(val != i)
            tmp = tmp.next;
            i++;
            if(tmp.next == null)
                abort = true;
                break;
        if(abort)
            return null;
        else
            return tmp.element;
    public int size()
        int size = 0;
        Node tmp = header;
        while(tmp.element != null)
            tmp = tmp.next;
            size++;
        return size;
}And here's the SortedPhoneDirectory:
class SortedPhoneDirectory extends PhoneDirectory
    private Node header;
    public SortedPhoneDirectory()
        header = new Node(null);
    public void insert(Person o)
        Node newNode = new Node();
        newNode.element = o;
        if(header.element == null)
            header = newNode;
        else if(header.element.getName().compareToIgnoreCase(o.getName()) >= 0)
            newNode.next = header;
            header = newNode;
        else
            Node runner = header.next;
            Node previous = header;
            while(runner != null && runner.element.getName().compareToIgnoreCase(o.getName()) < 0)
                previous = runner;
                runner = runner.next;
            newNode.next = runner;
            previous.next = newNode;
}The class Node that the linkedlist contains:
class Node
    public Person element;
    public Node next;
      // Constructors
    public Node()
        next = null;
        element = null;
    public Node( Person theElement )
        this( theElement, null );
    public Node( Person theElement, Node n )
        element = theElement;
        next    = n;
}The class Person that the Nodes are containing:
class Person implements Comparable
    private String name;
    private String address;
    private String phone;
    public Person( String n, String ad, String p )
        name = n; address = ad; phone = p;
    public String toString( )
        return getName( ) + "\t"+ getAdress()+ "\t" + getPhoneNumber( );
    public final String getName( )
        return name;
    public final String getAdress( )
        return address;
    public final String getPhoneNumber( )
        return phone;
    public int compareTo( Object other)
        Person p=(Person)other;
        if(name.compareTo(p.getName())<0)
            return -1;
        else if(name.compareTo(p.getName())>0)
            return 1;
        else
            return 0;
}And last my main program:
public class telefonKatalog
    static String name;
    static String address;
    static String phone;
    public static void main(String[] args)
        SortedPhoneDirectory catalog =new SortedPhoneDirectory();
        catalog.insert(new Person("Donald","Paris", "10245630"));    //I just use these for testing
        catalog.insert(new Person("Jacob","London", "63294063"));
        catalog.insert(new Person("Max","Rome", "63215371"));
        for(;;)
            System.out.println("\n\nMain Menu\n____________________\n");
            System.out.println("1. Add a new person to the Phone Directory.");
            System.out.println("2. Find a person in the Phone Directory.");
            System.out.println("3. Remove a person from the Phone Directory");
            System.out.println("4. Print the whole Phone Directory");
            System.out.println("5. Exit.\n");
            char choice = Keyboard.readChar();
            switch(choice)
                case '1':
                    System.out.println("\nAdd a new person to the Phone Directory\n______________________________________\n");
                    System.out.println("Name: ");
                    name = Keyboard.readString();
                    System.out.println("\nAdress: ");
                    address = Keyboard.readString();
                    System.out.println("\nPhone Number: ");
                    phone = Keyboard.readString();
                    catalog.insert(new Person(name, address, phone));
                    System.out.println("\nThe person has been added.\n");
                    break;
                case '2':
                    System.out.println("\nFind a person in the Phone Directory.\n_________________________________\n");
                    System.out.println("1. Find by name.");
                    System.out.println("2. Find by address.");
                    System.out.println("3. Find by phone number\n");
                    choice = Keyboard.readChar();
                    switch(choice)
                        case '1':
                            System.out.println("\nFind by name.\n___________________\n");
                            System.out.println("Write the name of the person you are looking for:\n");
                            name = Keyboard.readString();
                            System.out.println();
                            catalog.findWithName(name);
                            break;
                        case '2':
                            System.out.println("\nFind by address.\n___________________\n");
                            System.out.println("Write the address:\n");
                            address = Keyboard.readString();
                            System.out.println();
                            catalog.findWithAdress(address);
                            break;
                        case '3':
                            System.out.println("\nFind by Phone Number.\n___________________\n");
                            System.out.println("Write the phone number:\n");
                            address = Keyboard.readString();
                            System.out.println();
                            catalog.findWithPhone(address);
                            break;
                        default:
                            System.out.println("\nUnvalid character!\n");
                            break;
                    break;
                case '3':
                    System.out.println("\nRemove a person from the Phone Directory.\n____________________________________\n");
                    System.out.println("Write the name of the person you want to remove.\n");
                    String strChoice = Keyboard.readString();
                    boolean result = false;
                    for(int i = 0; i < catalog.size(); i++)
                        name = catalog.get(i).getName();
                        if(name.contains(strChoice))
                            catalog.remove(i);
                            System.out.println(name + " has been removed");
                            result = true;
                    if(!result)
                        System.out.println("There are no such person");
                    break;
                case '4':
                    System.out.println("\nThe whole Phone Directory: \n_____________________________\n");
                    catalog.print();
                    System.out.println("\n_____________________________\n");
                    break;
                case '5':
                    System.exit(0);
                default:
                    System.out.println("\nUnvalid character!\n");
}Its pretty long, sorry about that.. =)
In the main program it all workes perfectly apart from the sorting if you change
SortedPhoneDirectory catalog = new SortedPhoneDirectory(); into PhoneDirectory catalog = new PhoneDirectory();
What is wrong about this code?? :O:(
Edited by: YZF-R1 on 2008-maj-23 16:55

Answer 1

YZF-R1 wrote:
now thats just mean =( Why is that mean? I mean, you didn't learn something soon enough, and I am mean for not spoon feeding you the answer so that you can cheat by handing in work that is not your own? You already did that you just told us! This is called plagiarism and could get you expelled from school.
I will sit down and learn all of that later when I have time, Sure. You should have learnt it sooner.
but my deadline is tomorrow and its the last project of the course, so the teacher thought he would make up something extra. When I asked him if he could help me with my problem he couldn't even fix it, he thought everything looked as it was supposed to and so on.. :'( Come on, pleease :'(Christ, stop that!