Llist.java? llistnumbernode.java? PLEASE HELP

Question

I'm programming linked-list. I know how to program, not that well though, but I don't understand how the linked-list works.
Here's what I got so far:
import java.util.*;
** Author: Yuan-Fang Wang
** The skeleton of a singly-linked-list class using interface
** DO NOT delete anything or change any parameters or return types
public class llist {
   int   length; // number of nodes in the list, for am empty list length = 0
   node  head;     // must poinnt to the head (the first element) of the list
   // interface definition of a node
   public interface node {
      public Object getValue();          // get stored KEY value
      public node   getNext();          // get next node
      public void   setNext(node l);     // set next node
      public int    compares(node l);     // compare values
      public String toString();          // for printing
   // constructor for a null list
   public llist() {
        head = null;
        length = 0;
   // constructor using the first node
   public llist(node l) {
             head = l;
             length++;
   // truncate the linked list to null
   public void empty() {
     //head.setNext(null);
   // don't change anything here
   public Enumeration getEnum() {
      return new Enumeration () {
      node current = head;
      public boolean hasMoreElements() {
         return (current!=null);
      public Object nextElement() {
         if (current==null) throw new NoSuchElementException("Linkedlist");
         Object value = current;
         current = current.getNext();
         return value;
   // return the number of nodes in the linked-list
   public int getLength() {
        return length;
   // search for a node in the linked-list
   // return its position in the linked list (the first node is 0)
   // return -1 if the node is not found in the linked list
   public int search(node elem) {
      while(head != null){
   // insert a node into the linked list
   // return its position in the linked list (the first node is 0)
   // return -1 if the node already in the linked list (no duplicated insert)
   public int insert(node elem) {
     if(head==null){
          head = elem;
          length++;
          return 0;
     else if(elem<head){
          elem.setNext(head);
          head = elem;
          length++;
          return 0;
     else{
          ptr = head;
          while(ptr != null){
               if(ptr == elem)     return -1;     //duplicate
               else if(ptr.getNext() != null
      return -1; // you must change this line to return the true insert result
   // delete a node from the linked list
   // return deleted node if is in the linked list and null otherwise
   public node delete(node elem) {
      return null; // you must change this line to return true delete result
   // return the n-th node of the linked list
   // return null if n is < 0 or larger than or equal to the current length
   public node findNth(int n) {
      return null; // you must change this line to return true findnth result
   // print the list, DO NOT modify this method in anyway
   public void printList() {
      node ptr = head;
      while (ptr!=null) {
      System.out.print(ptr + " ");
      ptr = ptr.getNext();
      System.out.println();
   // utility routine that will be used later, DO NOT modify this method
   node findLast() {
      if (head==null) return null;
      node ptr = head;
      while (ptr.getNext()!=null) {
      ptr = ptr.getNext();
      return ptr;
}And for llistnumbernode.java
** Author: Yuan-Fang Wang
** The skeleton of a singly-linked-list node using interface
** DO NOT delete anything or change any parameters or return types
public class llistnumbernode implements llist.node {
   Number element;     // stored element
   llist.node   next;          // next node
   public llistnumbernode (Number elem) {
   // return the KEY value for comparison
   public Object getValue() {
      return null; // you must change this to return true result of getValue()
   // get the next node in the list
   public llist.node getNext() {
      return null; // you must change this to return true result of getNext()
   // set the next node in the list
   public void setNext(llist.node l) {
   // return  1 if this (self) >  node l
   // return  0 if this (self) == node l
   // return -1 if this (self) <  node l
   public int compares(llist.node l) {
      return -1; // you must change this to return true result of compares()
   // DO NOT change this method
   public String toString() {
      return element.toString();
}Please HELPPPPP

Answer 1

Will someone please help!!!