# Linked List in C++

A linked list is a linear data structure, in which the elements are not stored at contiguous memory locations. The elements in a linked list are linked using pointers as shown in the below image

![](/files/-M9kwNKRW4mFu7gMBe-H)

In simple words, a linked list consists of nodes where each node contains a data field and a reference(link) to the next node in the list.

### Singly Linked List

 **Setup Algorithms** 

```c
class Node  
{  
    public: 
    int data;  
    Node *next;  
};  
```

Example simple  for **Singly Linked List** with 3 Node 

```c
int main() 
{ 
    Node* head = NULL; 
    Node* second = NULL; 
    Node* third = NULL; 
  
    // allocate 3 nodes in the heap 
    head = new Node(); 
    second = new Node(); 
    third = new Node(); 
  
    /* Three blocks have been allocated dynamically.  
    We have pointers to these three blocks as head,  
    second and third      
    head         second         third  
        |             |             |  
        |             |             |  
    +---+-----+     +----+----+     +----+----+  
    | # | # |     | # | # |     | # | # |  
    +---+-----+     +----+----+     +----+----+  
      
# represents any random value.  
Data is random because we haven’t assigned  
anything yet */
  
    head->data = 1; // assign data in first node 
    head->next = second; // Link first node with 
    // the second node 
  
    /* data has been assigned to the data part of first  
    block (block pointed by the head). And next  
    pointer of the first block points to second.  
    So they both are linked.  
  
    head         second         third  
        |             |             |  
        |             |             |  
    +---+---+     +----+----+     +-----+----+  
    | 1 | o----->| # | # |     | # | # |  
    +---+---+     +----+----+     +-----+----+      
*/
  
    // assign data to second node 
    second->data = 2; 
  
    // Link second node with the third node 
    second->next = third; 
  
    /* data has been assigned to the data part of the second  
    block (block pointed by second). And next  
    pointer of the second block points to the third  
    block. So all three blocks are linked.  
      
    head         second         third  
        |             |             |  
        |             |             |  
    +---+---+     +---+---+     +----+----+  
    | 1 | o----->| 2 | o-----> | # | # |  
    +---+---+     +---+---+     +----+----+     */
  
    third->data = 3; // assign data to third node 
    third->next = NULL; 
  
    /* data has been assigned to the data part of the third  
    block (block pointed by third). And next pointer  
    of the third block is made NULL to indicate  
    that the linked list is terminated here.  
  
    We have the linked list ready.  
  
        head      
            |  
            |  
        +---+---+     +---+---+     +----+------+  
        | 1 | o----->| 2 | o-----> | 3 | NULL |  
        +---+---+     +---+---+     +----+------+      
      
      
    Note that only the head is sufficient to represent  
    the whole list. We can traverse the complete  
    list by following the next pointers. */
  
    return 0; 
} 
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://pea-story.gitbook.io/pexpa/experience/linked-list-in-c++.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.