# Program To Delete A Node From The End Of The Singly Linked List

Program To Delete A Node From The End Of The Singly Linked List on fibonacci, factorial, prime, armstrong, swap, reverse, search, sort, stack, queue, array, linkedlist, tree, graph etc.

## Program to delete a node from the end of the singly linked list

### Explanation

In this program, we will create a singly linked list and delete a node from the end of the list. To accomplish this task, we first find out the second last node of the list. Then, make second last node as the new tail of the list. Then, delete the last node of the list.

In the above example, Node was the tail of the list. Traverse through the list to find out the second last node which in this case is node 4. Make node 4 as the tail of the list. Node 4's next will point to null.

### Algorithm

1. Create a class Node which has two attributes: data and next. Next is a pointer to the next node in the list.
2. Create another class DeleteEnd which has two attributes: head and tail.
1. Create a new node.
2. It first checks, whether the head is equal to null which means the list is empty.
3. If the list is empty, both head and tail will point to a newly added node.
4. If the list is not empty, the new node will be added to end of the list such that tail's next will point to a newly added node. This new node will become the new tail of the list.
4. DeleteFromEnd() will delete a node from the end of the list:
1. It first checks whether the head is null (empty list) then, display the message "List is empty" and return.
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, traverse through the list till node current points to second last node in the list.
5. Node current will become the new tail of the list.
6. Node next to current will be made null to delete the last node.
5. display() will display the nodes present in the list:
1. Define a node current which will initially point to the head of the list.
2. Traverse through the list till current points to null.
3. Display each node by making current to point to node next to it in each iteration.

### Python

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

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

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

#Checks if the list is empty
#If list is empty, both head and tail will point to new node
self.tail = newNode;
else:
#newNode will be added after tail such that tail's next will point to newNode
self.tail.next = newNode;
#newNode will become new tail of the list
self.tail = newNode;

#deleteFromEnd() will delete a node from end of the list
def deleteFromEnd(self):
#Checks if the list is empty
print("List is empty");
return;
else:
#Checks whether the list contains only one element
#Loop through the list till the second last element such that current.next is pointing to tail
while(current.next != self.tail):
current = current.next;
#Second last element will become new tail of the list
self.tail = current;
self.tail.next = None;

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

#display() will display all the nodes present in 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;

sList = DeleteEnd();

#Printing original list
print("Original List: ");
sList.display();

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

Output:

``` Original 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 singly linked list
struct node{
int data;
struct node *next;
};

struct node *head, *tail = NULL;

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

//Checks if the list is empty
//If list is empty, both head and tail will point to new node
tail = newNode;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail->next = newNode;
//newNode will become new tail of the list
tail = newNode;
}
}

//deleteFromEnd() will delete a node from end of the list
void deleteFromEnd() {

//Checks if the list is empty
printf("List is empty \n");
return;
}
else {
//Checks whether the list contains only one element
//Loop through the list till the second last element such that current.next is pointing to tail
while(current->next != tail) {
current = current->next;
}
//Second last element will become new tail of the list
tail = current;
tail->next = NULL;
}
//If the list contains only one element
//Then it will remove it and both head and tail will point to NULL
else {
}
}
}

//display() will display all the nodes present in 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
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 singly linked list
class Node{
int data;
Node next;

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

public Node tail = null;

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

//Checks if the list is empty
//If list is empty, both head and tail will point to new node
tail = newNode;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail.next = newNode;
//newNode will become new tail of the list
tail = newNode;
}
}

//deleteFromEnd() will delete a node from end of the list
public void deleteFromEnd() {

//Checks if the list is empty
System.out.println("List is empty");
return;
}
else {
//Checks whether the list contains only one element
//Loop through the list till the second last element such that current.next is pointing to tail
while(current.next != tail) {
current = current.next;
}
//Second last element will become new tail of the list
tail = current;
tail.next = null;
}
//If the list contains only one element
//Then it will remove it and both head and tail will point to null
else {
}
}
}

//display() will display all the nodes present in 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 pointer
System.out.print(current.data + " ");
current = current.next;
}
System.out.println();
}

public static void main(String[] args) {

DeleteEnd sList = new DeleteEnd();

//Printing original list
System.out.println("Original List: ");
sList.display();

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

Output:

```Original 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 CreateList
{
//Represent a node of the singly linked list
public class Node<T>{
public T data;
public Node<T> next;

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

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

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

//Checks if the list is empty
//If list is empty, both head and tail will point to new node
tail = newNode;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail.next = newNode;
//newNode will become new tail of the list
tail = newNode;
}
}

//deleteFromEnd() will delete a node from end of the list
public void deleteFromEnd() {

//Checks if the list is empty
Console.WriteLine("List is empty");
return;
}
else {
//Checks whether the list contains only one element
//Loop through the list till the second last element such that current.next is pointing to tail
while(current.next != tail) {
current = current.next;
}
//Second last element will become new tail of the list
tail = current;
tail.next = null;
}
//If the list contains only one element
//Then it will remove it and both head and tail will point to null
else {
}
}
}

//display() will display all the nodes present in 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 pointer
Console.Write(current.data + " ");
current = current.next;
}
Console.WriteLine();
}
}

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

//Printing original list
Console.WriteLine("Original List: ");
sList.display();

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

Output:

```Original 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 singly linked list
class Node{
public \$data;
public \$next;

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

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

//Checks if the list is empty
//If list is empty, both head and tail will point to new node
\$this->tail = \$newNode;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
\$this->tail->next = \$newNode;
//newNode will become new tail of the list
\$this->tail = \$newNode;
}
}

//deleteFromEnd() will delete a node from end of the list
function deleteFromEnd() {

//Checks if the list is empty
print("List is empty");
return;
}
else {
//Checks whether the list contains only one element
//Loop through the list till the second last element such that current.next is pointing to tail
while(\$current->next != \$this->tail) {
\$current = \$current->next;
}
//Second last element will become new tail of the list
\$this->tail = \$current;
\$this->tail->next = null;
}
//If the list contains only one element
//Then it will remove it and both head and tail will point to null
else {
}
}
}

//display() will display all the nodes present in 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>");
}
}

\$sList = new DeleteEnd();

//Printing original list
print("Original List: <br>");
\$sList->display();

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

Output:

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

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