linked list in c

Linked List in C

A linked list is a data structure that consists of a sequence of nodes, where each node contains data and a reference (or link) to the next node in the sequence. In C, a linked list can be implemented using structures and pointers.

Here are the steps to create a linked list in C:

1. Define the structure for the linked list node:
2. Create a structure that represents a node in the linked list.
3. The structure should contain two members: one for storing the data and another for storing the reference to the next node.

4. For example: c struct Node { int data; struct Node* next; };

5. Create the head (or start) of the linked list:

6. Declare a pointer variable to the first node of the linked list, often called the "head" or "start" of the list.
7. Initialize the head pointer to NULL to indicate an empty list.

8. For example: c struct Node* head = NULL;

9. Insert nodes into the linked list:

10. To insert a new node at the beginning of the linked list:
    • Create a new node using dynamic memory allocation (malloc or calloc).
    • Assign the data value to the new node.
    • Set the next pointer of the new node to the current head of the list.
    • Update the head pointer to point to the new node.
11. To insert a new node at the end of the linked list:
    • Create a new node using dynamic memory allocation.
    • Assign the data value to the new node.
    • Set the next pointer of the new node to NULL.
    • Traverse the linked list from the head to the last node.
    • Update the next pointer of the last node to point to the new node.

12. For example, to insert a node at the beginning: c struct Node newNode = (struct Node)malloc(sizeof(struct Node)); newNode->data = newData; newNode->next = head; head = newNode;

13. Traverse the linked list:

14. To access or print the elements of the linked list, you need to traverse through each node.
15. Start from the head and follow the next pointers until you reach the end of the list (where next is NULL).

16. For example: c struct Node* current = head; while (current != NULL) { // Access or print the data of the current node printf("%d ", current->data); // Move to the next node current = current->next; }

17. Delete nodes from the linked list:

18. To delete a node from the linked list:
    • Find the node to be deleted and its previous node.
    • Update the next pointer of the previous node to skip the node to be deleted.
    • Free the memory allocated for the node to be deleted using free.

19. For example, to delete the first node: c struct Node* temp = head; head = head->next; free(temp);

20. Free memory:

21. After you are done with the linked list, make sure to free the memory allocated for each node.
22. Traverse through the linked list and use free to release the memory for each node.
23. For example: c struct Node* current = head; while (current != NULL) { struct Node* temp = current; current = current->next; free(temp); }

These are the basic steps to create, insert, traverse, delete, and free a linked list in C. Remember to handle edge cases, such as an empty list or deleting the last node, appropriately in your implementation.

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