Doubly Linked List
Doubly Linked List
public class DoublyLinkedList {
static DNode root;
static DNode temp;
static DNode current;
public void addNodes(int data){
DNode dNode = new DNode(data);
if(root==null){
root = dNode;
root.previousNode = null;
root.nextNode = null;
}else{
current = root;
while(current.nextNode!=null){
current = current.nextNode;
}
current.nextNode = dNode;
dNode.previousNode = current;
dNode.nextNode = null;
}
}
public void insertNode(int data, int after){
DNode dNode = new DNode(data);
int ithNode = 1;
current = root;
while(ithNode != after){
current = current.nextNode;
ithNode++;
}
temp = current.nextNode;
current.nextNode = dNode;
dNode.nextNode = temp;
temp.previousNode = dNode;
dNode.previousNode = current;
}
public void deleteNode(int nodeNumber){
int ithNode = 1;
current = root;
if(nodeNumber==1){
root = current.nextNode;
current.nextNode = null;
current.previousNode = null;
}else{
while(ithNode != nodeNumber){
current = current.nextNode;
ithNode++;
}
if(current.nextNode == null){
current.previousNode.nextNode = null;
current.previousNode = null;
}else{
current.previousNode.nextNode = current.nextNode;
current.nextNode.previousNode = current.previousNode;
}
}
}
public void print(){
current = root;
boolean arrow = true;
do{
System.out.print((arrow) ? "|" + current.data + "|" : " --> " + "|" + current.data + "|" );
arrow = false;
current = current.nextNode;
}while(current!=null);
}
public void printBackwards(){
current = root;
boolean arrow = true;
while(current.nextNode!=null){
current = current.nextNode;
}
do{
System.out.print((arrow) ? "|" + current.data + "|" : " --> " + "|" + current.data + "|" );
arrow = false;
current = current.previousNode;
}while(current.previousNode!=null);
System.out.print(" --> " + "|" + current.data + "|" );
}
public static void main(String[] args){
DoublyLinkedList list = new DoublyLinkedList();
list.addNodes(1);
list.addNodes(2);
list.addNodes(3);
list.addNodes(4);
list.addNodes(5);
list.addNodes(6);
list.print();
System.out.println();
list.printBackwards();
System.out.println();
System.out.println("The number of DNodes in the Linked List is " + DNode.noOfLinkedList);
}
}
public class DNode {
static int noOfLinkedList = 0;
int data;
DNode previousNode;
DNode nextNode;
DNode(int data){
this.data = data;
noOfLinkedList++;
}
}