# Program to Delete a New Node From the End of the Doubly Linked List

Program to Delete a New Node From the End of the Doubly Linked List on fibonacci, factorial, prime, armstrong, swap, reverse, search, sort, stack, queue, array, linkedlist, tree, graph etc.

## Q. Program to delete a new node from the end of the doubly linked list.

### Explanation

In this program, we will create a doubly linked list and delete a node from the end of the list. If the list is empty, print the message "List is empty". If the list is not empty, tail's previous node will become the new tail of the list thus, deleting the last node from the list.

In above example, node new was the tail of the list. Make tail's previous node that is, node 4 as the tail of the list. Node 4's next will point to null.

### Algorithm

1. Define a Node class which represents a node in the list. It will have three properties: data, previous which will point to the previous node and next which will point to the next node.
2. Define another class for creating the doubly linked list, and it has two nodes: head and tail. Initially, head and tail will point to null.
3. deleteFromEnd() will delete a node from the end of the list:
1. It first checks whether the head is null (empty list) then, it will return from the function as there is no node present in the list.
2. If the list is not empty, it will check whether the list has only one node.
3. If the list has only one node, it will set both head and tail to null.
4. If the list has more than one node then, tail's previous node will become the new tail of the list.
5. This new tail will point to null thus, delete the last node of the list.
4. display() will show all the nodes present in the list.
1. Define a new node 'current' that will point to the head.
2. Print current.data till current points to null.
3. Current will point to the next node in the list in each iteration.

## Solution

### Python

```#Represent a node of doubly linked list
class Node:
def __init__(self,data):
self.data = data;
self.previous = None;
self.next = None;

class DeleteEnd:
def __init__(self):
self.tail = None;

#Create a new node
newNode = Node(data);

#If list is empty
#Both head and tail will point to newNode
#head's previous will point to None
#tail's next will point to None, as it is the last node of the list
self.tail.next = None;
else:
#newNode will be added after tail such that tail's next will point to newNode
self.tail.next = newNode;
#newNode's previous will point to tail
newNode.previous = self.tail;
#newNode will become new tail
self.tail = newNode;
#As it is last node, tail's next will point to None
self.tail.next = None;

#deleteFromEnd() will delete a node from the end of the list
def deleteFromEnd(self):
#Checks whether list is empty
return;
else:
#Checks whether the list contains only one node
#Previous node to the tail will become new tail
self.tail = self.tail.previous;
#Node next to current tail will be made None
self.tail.next = None;

#If the list contains only one element
#Then it will remove the node, and now both head and tail will point to None

else:

#display() will print out the nodes of the list
def display(self):
#Node current will point to head
print("List is empty");
return;
while(current != None):
#Prints each node by incrementing pointer.
print(current.data),
current = current.next;
print();

dList = DeleteEnd();

#Printing original list
print("Original List: ");
dList.display();
dList.deleteFromEnd();
#Printing updated list
print("Updated List: ");
dList.display();
```

Output:

```Original List:
1 2 3 4 5
Updated List:
1 2 3 4
Updated List:
1 2 3
Updated List:
1 2
Updated List:
1
Updated List:
List is empty
```

### C

```#include <stdio.h>

//Represent a node of the doubly linked list

struct node{
int data;
struct node *previous;
struct node *next;
};

struct node *head, *tail = NULL;

//Create a new node
struct node *newNode = (struct node*)malloc(sizeof(struct node));
newNode->data = data;

//If list is empty
//Both head and tail will point to newNode
//head's previous will point to NULL
//tail's next will point to NULL, as it is the last node of the list
tail->next = NULL;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail->next = newNode;
//newNode's previous will point to tail
newNode->previous = tail;
//newNode will become new tail
tail = newNode;
//As it is last node, tail's next will point to NULL
tail->next = NULL;
}
}

//deleteFromEnd() will delete a node from the end of the list
void deleteFromEnd() {
//Checks whether list is empty
return;
}
else {
//Checks whether the list contains only one node
//Previous node to the tail will become new tail
tail = tail->previous;
//Node next to current tail will be made NULL
tail->next = NULL;
}
//If the list contains only one element
//Then it will remove node and now both head and tail will point to NULL
else {
}
}
}

//display() will print out the nodes of the list
void display() {
//Node current will point to head
printf("List is empty\n");
return;
}
while(current != NULL) {
//Prints each node by incrementing pointer.
printf("%d ",current->data);
current = current->next;
}
printf("\n");
}

int main()
{

//Printing original list
printf("Original List: \n");
display();
deleteFromEnd();
//Printing updated list
printf("Updated List: \n");
display();
}

return 0;
}
```

Output:

```Original List:
1 2 3 4 5
Updated List:
1 2 3 4
Updated List:
1 2 3
Updated List:
1 2
Updated List:
1
Updated List:
List is empty
```

### JAVA

```public class DeleteEnd {

//Represent a node of the doubly linked list

class Node{
int data;
Node previous;
Node next;

public Node(int data) {
this.data = data;
}
}

//Create a new node
Node newNode = new Node(data);

//If list is empty
//Both head and tail will point to newNode
//head's previous will point to null
//tail's next will point to null, as it is the last node of the list
tail.next = null;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail.next = newNode;
//newNode's previous will point to tail
newNode.previous = tail;
//newNode will become new tail
tail = newNode;
//As it is last node, tail's next will point to null
tail.next = null;
}
}

//deleteFromEnd() will delete a node from the end of the list
public void deleteFromEnd() {
//Checks whether list is empty
return;
}
else {
//Checks whether the list contains only one node
//Previous node to the tail will become new tail
tail = tail.previous;
//Node next to current tail will be made null
tail.next = null;
}
//If the list contains only one element
//Then it will remove node and now both head and tail will point to null
else {
}
}
}

//display() will print out the nodes of the list
public void display() {
//Node current will point to head
System.out.println("List is empty");
return;
}
while(current != null) {
//Prints each node by incrementing the pointer.

System.out.print(current.data + " ");
current = current.next;
}
System.out.println();
}

public static void main(String[] args) {

DeleteEnd dList = new DeleteEnd();

//Printing original list
System.out.println("Original List: ");
dList.display();
dList.deleteFromEnd();
//Printing updated list
System.out.println("Updated List: ");
dList.display();
}
}
}
```

Output:

```Original List:
1 2 3 4 5
Updated List:
1 2 3 4
Updated List:
1 2 3
Updated List:
1 2
Updated List:
1
Updated List:
List is empty
```

### C#

```using System;
{
public class Program
{
//Represent a node of the doubly linked list

public class Node<T>{
public T data;
public Node<T> previous;
public Node<T> next;

public Node(T value) {
data = value;
}
}

public class DeleteEnd<T>{
public Node<T> tail = null;

//Create a new node
Node<T> newNode = new Node<T>(data);

//If list is empty
//Both head and tail will point to newNode
//head's previous will point to null
//tail's next will point to null, as it is the last node of the list
tail.next = null;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail.next = newNode;
//newNode's previous will point to tail
newNode.previous = tail;
//newNode will become new tail
tail = newNode;
//As it is last node, tail's next will point to null
tail.next = null;
}
}

//deleteFromEnd() will delete a node from the end of the list
public void deleteFromEnd() {
//Checks whether list is empty
return;
}
else {
//Checks whether the list contains only one node
//Previous node to the tail will become new tail
tail = tail.previous;
//Node next to current tail will be made null
tail.next = null;
}
//If the list contains only one element
//Then it will remove node and now both head and tail will point to null
else {
}
}
}

//display() will print out the nodes of the list
public void display() {
//Node current will point to head
Console.WriteLine("List is empty");
return;
}
while(current != null) {
//Prints each node by incrementing the pointer.

Console.Write(current.data + " ");
current = current.next;
}
Console.WriteLine();
}
}

public static void Main()
{
DeleteEnd<int> dList = new DeleteEnd<int>();

//Printing original list
Console.WriteLine("Original List: ");
dList.display();
dList.deleteFromEnd();
//Printing updated list
Console.WriteLine("Updated List: ");
dList.display();
}
}
}
}
```

Output:

```Original List:
1 2 3 4 5
Updated List:
1 2 3 4
Updated List:
1 2 3
Updated List:
1 2
Updated List:
1
Updated List:
List is empty
```

### PHP

```<!DOCTYPE html>
<html>
<body>
<?php
//Represent a node of doubly linked list
class Node{
public \$data;
public \$previous;
public \$next;

function __construct(\$data){
\$this->data = \$data;
}
}
class DeleteEnd{
public \$tail;
function __construct(){
\$this->tail = NULL;
}

//Create a new node
\$newNode = new Node(\$data);

//If list is empty
//Both head and tail will point to newNode
//head's previous will point to NULL
//tail's next will point to NULL, as it is the last node of the list
\$this->tail->next = NULL;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
\$this->tail->next = \$newNode;
//newNode's previous will point to tail
\$newNode->previous = \$this->tail;
//newNode will become new tail
\$this->tail = \$newNode;
//As it is last node, tail's next will point to NULL
\$this->tail->next = NULL;
}
}

//deleteFromEnd() will delete a node from the end of the list
function deleteFromEnd() {
//Checks whether list is empty
return;
}
else {
//Checks whether the list contains only one node
//Previous node to the tail will become new tail
\$this->tail = \$this->tail->previous;
//Node next to current tail will be made null
\$this->tail->next = NULL;
}
//If the list contains only one element
//Then it will remove node and now both head and tail will point to null
else {
}
}
}

//display() will print out the nodes of the list
function display() {
//Node current will point to head
print("List is empty <br>");
return;
}
while(\$current != NULL) {
//Prints each node by incrementing pointer.
print(\$current->data . " ");
\$current = \$current->next;
}
print("<br>");
}
}

\$dList = new DeleteEnd();

//Printing original list
print("Original List: <br>");
\$dList->display();
\$dList->deleteFromEnd();
//Printing updated list
print("Updated List: <br>");
\$dList->display();
}
?>
</body>
</html>
```

Output:

```Original List:
1 2 3 4 5
Updated List:
1 2 3 4
Updated List:
1 2 3
Updated List:
1 2
Updated List:
1
Updated List:
List is empty
```

Next Topic#