Linked List in C: A Complete Guide with Examples

A linked list is a fundamental data structure in C programming that provides a flexible way to store and manage data. Unlike arrays, linked lists do not require a predefined size and allow dynamic memory allocation. This makes them especially useful in applications where the number of data elements is unpredictable.

1. What is a Linked List?

A linked list is a collection of nodes where each node contains two parts: data and a pointer to the next node. This structure allows efficient insertion and deletion of elements.

2. Types of Linked Lists

• Singly Linked List: Each node points to the next node.
• Doubly Linked List: Each node points to both the previous and next nodes.
• Circular Linked List: The last node points back to the first node.

3. Structure of a Singly Linked List Node

struct Node {
  int data;
  struct Node* next;
};

4. Basic Operations on Linked Lists

• Insertion: Add a node at the beginning, middle, or end.
• Deletion: Remove a node by position or value.
• Traversal: Navigate through the list to access or display nodes.
• Search: Find a specific node based on its value.

5. Example: Creating and Traversing a Singly Linked List

#include <stdio.h>
#include <stdlib.h>

struct Node {
  int data;
  struct Node* next;
};

void printList(struct Node* n) {
  while (n != NULL) {
    printf("%d -> ", n->data);
    n = n->next;
  }
  printf("NULL\n");
}

int main() {
  struct Node* head = NULL;
  struct Node* second = NULL;
  struct Node* third = NULL;

  head = (struct Node*) malloc(sizeof(struct Node));
  second = (struct Node*) malloc(sizeof(struct Node));
  third = (struct Node*) malloc(sizeof(struct Node));

  head->data = 1;
  head->next = second;

  second->data = 2;
  second->next = third;

  third->data = 3;
  third->next = NULL;

  printList(head);
  return 0;
}

6. Advantages of Linked Lists

• Dynamic size allocation
• Efficient insertion/deletion
• Better memory utilization

7. Disadvantages of Linked Lists

• More memory usage due to pointers
• Slower access time compared to arrays
• Complexity in reverse traversal (in singly linked lists)

8. Real-World Applications

• Implementing stacks and queues
• Dynamic memory allocation systems
• Graph representations (adjacency lists)
• Symbol tables in compilers

Conclusion

Linked lists in C offer a powerful alternative to arrays, especially when dealing with dynamic data. They are essential for mastering data structures and algorithms, and play a key role in various programming scenarios. Start experimenting with linked lists to enhance your understanding of memory management and pointer manipulation in C.

Keywords: Linked List in C, C Linked List Tutorial, Singly Linked List in C, C Programming Data Structures, C Dynamic Memory