# Linked List - Delete a node at the given position

In this method, a node at the specified position in the linked list is deleted. For example - if the given List is 10->20->30 and the 2nd node is deleted, the Linked List becomes 10->20.

First, the specified position must be greater than equal to 1. If the specified position is 1 and head is not null, then make the head next as head and delete the previous head. Else, traverse to the node that is previous to the specified position. If the specified node and previous to the specified node are not null then adjust the link. In other case, the specified node will be already null. The below figure describes the process, if the deletion node is other than the head node. The function pop_at is created for this purpose. It is a 5-step process.

```void pop_at(int position) {

//1. check if the position is > 0
if(position < 1) {
cout<<"\nposition should be >= 1.";
} else if (position == 1 && head != NULL) {

//2. if the position is 1 and head is not null, make
free(nodeToDelete);
} else {

//3. Else, make a temp node and traverse to the
//   node previous to the position
for(int i = 1; i < position-1; i++) {
if(temp != NULL) {
temp = temp->next;
}
}

//4. If the previous node and next of the previous
if(temp != NULL && temp->next != NULL) {
Node* nodeToDelete = temp->next;
temp->next = temp->next->next;
free(nodeToDelete);
} else {

//5. Else the given node will be empty.
}
}
}
```
```void pop_at(struct Node** head_ref, int position) {

//1. check if the position is > 0
if(position < 1) {
printf("\nposition should be >= 1.");
} else if (position == 1 && *head_ref != NULL) {

//2. if the position is 1 and head is not null, make
free(nodeToDelete);
} else {

//3. Else, make a temp node and traverse to the
//   node previous to the position
struct Node *temp;
for(int i = 1; i < position-1; i++) {
if(temp != NULL) {
temp = temp->next;
}
}

//4. If the previous node and next of the previous
if(temp != NULL && temp->next != NULL) {
struct Node* nodeToDelete = temp->next;
temp->next = temp->next->next;
free(nodeToDelete);
} else {

//5. Else the given node will be empty.
}
}
}
```
```def pop_at(self, position):

#1. check if the position is > 0
if(position < 1):
print("\nposition should be >= 1.")
elif (position == 1 and self.head != None):

#2. if the position is 1 and head is not null, make
nodeToDelete = None
else:

#3. Else, make a temp node and traverse to the
#   node previous to the position
for i in range(1, position-1):
if(temp != None):
temp = temp.next

#4. If the previous node and next of the previous
if(temp != None and temp.next != None):
nodeToDelete = temp.next
temp.next = temp.next.next
nodeToDelete = None
else:

#5. Else the given node will be empty.
```
```void pop_at(int position) {

//1. check if the position is > 0
if(position < 1) {
System.out.print("\nposition should be >= 1.");
} else if (position == 1 && head != null) {

//2. if the position is 1 and head is not null, make
nodeToDelete = null;
} else {

//3. Else, make a temp node and traverse to the
//   node previous to the position
Node temp = new Node();
for(int i = 1; i < position-1; i++) {
if(temp != null) {
temp = temp.next;
}
}

//4. If the previous node and next of the previous
if(temp != null && temp.next != null) {
Node nodeToDelete = temp.next;
temp.next = temp.next.next;
nodeToDelete = null;
} else {

//5. Else the given node will be empty.
}
}
}
```
```public void pop_at(int position) {

//1. check if the position is > 0
if(position < 1) {
Console.Write("\nposition should be >= 1.");
} else if (position == 1 && head != null) {

//2. if the position is 1 and head is not null, make
nodeToDelete = null;
} else {

//3. Else, make a temp node and traverse to the
//   node previous to the position
Node temp = new Node();
for(int i = 1; i < position-1; i++) {
if(temp != null) {
temp = temp.next;
}
}

//4. If the previous node and next of the previous
if(temp != null && temp.next != null) {
Node nodeToDelete = temp.next;
temp.next = temp.next.next;
nodeToDelete = null;
} else {

//5. Else the given node will be empty.
}
}
}
```
```public function pop_at(\$position) {

//1. check if the position is > 0
if(\$position < 1) {
echo "\nposition should be >= 1.";
} else if (\$position == 1 && \$this->head != null) {

//2. if the position is 1 and head is not null, make
\$nodeToDelete = null;
} else {

//3. Else, make a temp node and traverse to the
//   node previous to the position
\$temp = new Node();
for(\$i = 1; \$i < \$position-1; \$i++) {
if(\$temp != null) {
\$temp = \$temp->next;
}
}

//4. If the previous node and next of the previous
if(\$temp != null && \$temp->next != null) {
\$nodeToDelete = \$temp->next;
\$temp->next = \$temp->next->next;
\$nodeToDelete = null;
} else {

//5. Else the given node will be empty.
echo "\nThe node is already null.";
}
}
}
```

The below is a complete program that uses above discussed concept to delete a node at a given position in the linked list.

```#include <iostream>
using namespace std;

//node structure
struct Node {
int data;
Node* next;
};

private:
public:
}

//Add new element at the end of the list
void push_back(int newElement) {
Node* newNode = new Node();
newNode->data = newElement;
newNode->next = NULL;
} else {
while(temp->next != NULL)
temp = temp->next;
temp->next = newNode;
}
}

//Delete an element at the given position
void pop_at(int position) {
if(position < 1) {
cout<<"\nposition should be >= 1.";
} else if (position == 1 && head != NULL) {
free(nodeToDelete);
} else {
for(int i = 1; i < position-1; i++) {
if(temp != NULL) {
temp = temp->next;
}
}
if(temp != NULL && temp->next != NULL) {
Node* nodeToDelete = temp->next;
temp->next = temp->next->next;
free(nodeToDelete);
} else {
}
}
}

//display the content of the list
void PrintList() {
if(temp != NULL) {
cout<<"The list contains: ";
while(temp != NULL) {
cout<<temp->data<<" ";
temp = temp->next;
}
cout<<"\n";
} else {
cout<<"The list is empty.\n";
}
}
};

// test the code
int main() {

//Add three elements at the end of the list.
MyList.push_back(10);
MyList.push_back(20);
MyList.push_back(30);
MyList.PrintList();

//Delete an element at position 2
MyList.pop_at(2);
MyList.PrintList();

//Delete an element at position 1
MyList.pop_at(1);
MyList.PrintList();

return 0;
}
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```
```#include <stdio.h>
#include <stdlib.h>

//node structure
struct Node {
int data;
struct Node* next;
};

//Add new element at the end of the list
void push_back(struct Node** head_ref, int newElement) {
struct Node *newNode, *temp;
newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = newElement;
newNode->next = NULL;
} else {
while(temp->next != NULL) {
temp = temp->next;
}
temp->next = newNode;
}
}

//Delete an element at the given position
void pop_at(struct Node** head_ref, int position) {
if(position < 1) {
printf("\nposition should be >= 1.");
} else if (position == 1 && *head_ref != NULL) {
free(nodeToDelete);
} else {
struct Node *temp;
for(int i = 1; i < position-1; i++) {
if(temp != NULL) {
temp = temp->next;
}
}
if(temp != NULL && temp->next != NULL) {
struct Node* nodeToDelete = temp->next;
temp->next = temp->next->next;
free(nodeToDelete);
} else {
}
}
}

//display the content of the list
printf("The list contains: ");
while (temp != NULL) {
printf("%i ",temp->data);
temp = temp->next;
}
printf("\n");
} else {
printf("The list is empty.\n");
}
}

// test the code
int main() {
struct Node* MyList = NULL;

//Add three elements at the end of the list.
push_back(&MyList, 10);
push_back(&MyList, 20);
push_back(&MyList, 30);
PrintList(MyList);

//Delete an element at position 2
pop_at(&MyList, 2);
PrintList(MyList);

//Delete an element at position 1
pop_at(&MyList, 1);
PrintList(MyList);

return 0;
}
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```
```# node structure
class Node:
def __init__(self, data):
self.data = data
self.next = None

def __init__(self):

#Add new element at the end of the list
def push_back(self, newElement):
newNode = Node(newElement)
return
else:
while(temp.next != None):
temp = temp.next
temp.next = newNode

#Delete an element at the given position
def pop_at(self, position):
if(position < 1):
print("\nposition should be >= 1.")
elif (position == 1 and self.head != None):
nodeToDelete = None
else:
for i in range(1, position-1):
if(temp != None):
temp = temp.next
if(temp != None and temp.next != None):
nodeToDelete = temp.next
temp.next = temp.next.next
nodeToDelete = None
else:

#display the content of the list
def PrintList(self):
if(temp != None):
print("The list contains:", end=" ")
while (temp != None):
print(temp.data, end=" ")
temp = temp.next
print()
else:
print("The list is empty.")

# test the code

#Add three elements at the end of the list.
MyList.push_back(10)
MyList.push_back(20)
MyList.push_back(30)
MyList.PrintList()

#Delete an element at position 2
MyList.pop_at(2)
MyList.PrintList()

#Delete an element at position 1
MyList.pop_at(1)
MyList.PrintList()
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```
```//node structure
class Node {
int data;
Node next;
};

}

//Add new element at the end of the list
void push_back(int newElement) {
Node newNode = new Node();
newNode.data = newElement;
newNode.next = null;
} else {
Node temp = new Node();
while(temp.next != null)
temp = temp.next;
temp.next = newNode;
}
}

//Delete an element at the given position
void pop_at(int position) {
if(position < 1) {
System.out.print("\nposition should be >= 1.");
} else if (position == 1 && head != null) {
nodeToDelete = null;
} else {
Node temp = new Node();
for(int i = 1; i < position-1; i++) {
if(temp != null) {
temp = temp.next;
}
}
if(temp != null && temp.next != null) {
Node nodeToDelete = temp.next;
temp.next = temp.next.next;
nodeToDelete = null;
} else {
}
}
}

//display the content of the list
void PrintList() {
Node temp = new Node();
if(temp != null) {
System.out.print("The list contains: ");
while(temp != null) {
System.out.print(temp.data + " ");
temp = temp.next;
}
System.out.println();
} else {
System.out.println("The list is empty.");
}
}
};

// test the code
public class Implementation {
public static void main(String[] args) {

//Add three elements at the end of the list.
MyList.push_back(10);
MyList.push_back(20);
MyList.push_back(30);
MyList.PrintList();

//Delete an element at position 2
MyList.pop_at(2);
MyList.PrintList();

//Delete an element at position 1
MyList.pop_at(1);
MyList.PrintList();
}
}
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```
```using System;

//node structure
class Node {
public int data;
public Node next;
};

}

//Add new element at the end of the list
public void push_back(int newElement) {
Node newNode = new Node();
newNode.data = newElement;
newNode.next = null;
} else {
Node temp = new Node();
while(temp.next != null)
temp = temp.next;
temp.next = newNode;
}
}

//Delete an element at the given position
public void pop_at(int position) {
if(position < 1) {
Console.Write("\nposition should be >= 1.");
} else if (position == 1 && head != null) {
nodeToDelete = null;
} else {
Node temp = new Node();
for(int i = 1; i < position-1; i++) {
if(temp != null) {
temp = temp.next;
}
}
if(temp != null && temp.next != null) {
Node nodeToDelete = temp.next;
temp.next = temp.next.next;
nodeToDelete = null;
} else {
}
}
}

//display the content of the list
public void PrintList() {
Node temp = new Node();
if(temp != null) {
Console.Write("The list contains: ");
while(temp != null) {
Console.Write(temp.data + " ");
temp = temp.next;
}
Console.WriteLine();
} else {
Console.WriteLine("The list is empty.");
}
}
};

// test the code
class Implementation {
static void Main(string[] args) {

//Add three elements at the end of the list.
MyList.push_back(10);
MyList.push_back(20);
MyList.push_back(30);
MyList.PrintList();

//Delete an element at position 2
MyList.pop_at(2);
MyList.PrintList();

//Delete an element at position 1
MyList.pop_at(1);
MyList.PrintList();
}
}
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```
```<?php
//node structure
class Node {
public \$data;
public \$next;
}

public function __construct(){
}

//Add new element at the end of the list
public function push_back(\$newElement) {
\$newNode = new Node();
\$newNode->data = \$newElement;
\$newNode->next = null;
} else {
\$temp = new Node();
while(\$temp->next != null) {
\$temp = \$temp->next;
}
\$temp->next = \$newNode;
}
}

//Delete an element at the given position
public function pop_at(\$position) {
if(\$position < 1) {
echo "\nposition should be >= 1.";
} else if (\$position == 1 && \$this->head != null) {
\$nodeToDelete = null;
} else {
\$temp = new Node();
for(\$i = 1; \$i < \$position-1; \$i++) {
if(\$temp != null) {
\$temp = \$temp->next;
}
}
if(\$temp != null && \$temp->next != null) {
\$nodeToDelete = \$temp->next;
\$temp->next = \$temp->next->next;
\$nodeToDelete = null;
} else {
echo "\nThe node is already null.";
}
}
}

//display the content of the list
public function PrintList() {
\$temp = new Node();
if(\$temp != null) {
echo "The list contains: ";
while(\$temp != null) {
echo \$temp->data." ";
\$temp = \$temp->next;
}
echo "\n";
} else {
echo "The list is empty.\n";
}
}
};

// test the code

//Add three elements at the end of the list.
\$MyList->push_back(10);
\$MyList->push_back(20);
\$MyList->push_back(30);
\$MyList->PrintList();

//Delete an element at position 2
\$MyList->pop_at(2);
\$MyList->PrintList();

//Delete an element at position 1
\$MyList->pop_at(1);
\$MyList->PrintList();
?>
```

The above code will give the following output:

```The list contains: 10 20 30
The list contains: 10 30
The list contains: 30
```

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