Java bidirectional linked list INSERT, delete, find operation with header

1. Create a node node for a doubly linked list
2. Establish the class LinkedList, the member head is a reference to the table header, define the operation method of the list in LinkedList.
PS: Insert delete operation to determine the POS, if at the end of the table, to be special to prevent the occurrence of null references.

 Public classNode {//Create a node for a doubly linked list PublicNode left;  PublicNode right;  Public intdata;  PublicNode () { This. left=NULL;  This. right=NULL;  This. data=0; }     PublicNode (intdata) {         This. data=data; }    }

Public classLinkedList { PublicNode head;//Reference to header address Public intlength;  PublicLinkedList () {//Establish head node length=0; Head=NewNode (); Head.data=0; Head.left=NULL; Head.right=NULL; }     Public BooleanInsert (intPos,node Node) {//Insert node node between nodes labeled Pos-1 and POSintCount=0; Node Prenode=Head;  while(prenode!=NULL&&count<pos-1) {            ++count; Prenode=Prenode.right; }        if(prenode==NULL|| Count!=pos-1){            return false; }        if(prenode.right==NULL) {Prenode.right=node; Node.left=Prenode; Node.right=NULL; ++length; return true; } Node NextNode=Prenode.right; Node.right=NextNode; Node.left=Prenode; Prenode.right=node; Nextnode.left=node; ++length; return true; }     Public BooleanDelete (intPOS) {//delete nodes at the specified locationif(pos<0| | pos>=length) {            return false; }        intCount=0; Node Curnode=Head;  while(count!=pos&&curnode!=NULL) {            ++count; Curnode=Curnode.right; }        if(count!=pos| | curnode==NULL) {            return false; }        if(curnode.right==NULL) {CurNode.left.right=NULL; Curnode=NULL; }        if(curnode.right!=NULL) {//beforecurnode.left.right=Curnode.right; CurNode.right.left=Curnode.left; }        --length; return true; }     Public intSize () {//returns the number of linked list elementsreturnlength; }     Public BooleanIsEmpty () {if(length==0) {            return true; }        return false; }     Public BooleanTraverse () {//Output list Node Prenode=Head;  while(prenode.right!=NULL) {Prenode=Prenode.right; System.out.print (Prenode.data+" "); }        return true; }     Public intGetData (intPOS) {//Get specified position node element node Prenode=Head; intCount=0;  while(count!=POS) {Prenode=Prenode.right; ++count; }        returnPrenode.data; }     Public BooleanDelete (node node) {//Delete node node Curnode=Head;  while(curnode!=node&&curnode!=NULL) {Curnode=Curnode.right; }        if(curnode!=node) {            return false; }        if(curnode.right!=NULL) {CurNode.left.right=Curnode.right; CurNode.right.left=Curnode.left; --length; return true; }        if(curnode.right==NULL) {CurNode.left.right=NULL; --length; return true; }        return false; }}

 Public classMain { Public Static voidMain (string[] args) {LinkedList link=NewLinkedList (); //System.out.println (link.head==null);Node node1=NewNode (1); Node Node2=NewNode (3); Node Node3=NewNode (5); Node Node4=NewNode (9); Node Node5=NewNode (2); BooleanF=link. Insert (1, Node1); F=link. Insert (2, Node2); F=link. Insert (3, NODE3); F=link. Insert (4, NODE4); F=link. Insert (5, NODE5); //System.out.println (Link.head.data); //System.out.println (Link.head.right.data); //System.out.println (f); //Node node=node1;Link. Delete (2); Link.        Delete (NODE5); Booleang=link.       Delete (NODE3); //System.out.println ("g=" +g); //While (node!=null) {//System.out.println (Node.data); //Node=node.right; // }System.out.println ("size=" +link.       Size ()); System.out.println ("IsEmpty?" +link.isempty ()); Link.       Traverse ();       System.out.println (); System.out.println ("Data2=" +link.getdata (2)); }}

Java bidirectional linked list INSERT, delete, find operation with header