Linked Lists in C
Until now, you have mostly used arrays to store data.
Arrays work well, but they have a big limitation — their size is fixed.
To overcome this problem, C provides a powerful dynamic data structure called a Linked List.
What Is a Linked List?
A linked list is a collection of nodes where each node:
- Stores data
- Stores the address of the next node
Nodes are connected using pointers.
Why Not Just Use Arrays?
Arrays have these limitations:
- Fixed size
- Insertion is expensive
- Deletion is difficult
Linked lists solve these problems by using dynamic memory allocation.
Structure of a Linked List Node
Each node contains:
- Data part
- Pointer to the next node
struct Node {
int data;
struct Node *next;
};
Creating a Node
Nodes are created dynamically using malloc().
struct Node *newNode;
newNode = (struct Node *)malloc(sizeof(struct Node));
newNode->data = 10;
newNode->next = NULL;
Linking Nodes Together
Let’s create two nodes and connect them.
struct Node *head, *second;
head = (struct Node *)malloc(sizeof(struct Node));
second = (struct Node *)malloc(sizeof(struct Node));
head->data = 5;
head->next = second;
second->data = 15;
second->next = NULL;
Here, head points to the first node.
Traversing a Linked List
Traversal means visiting each node one by one.
struct Node *temp = head;
while (temp != NULL) {
printf("%d ", temp->data);
temp = temp->next;
}
Real-World Analogy
Think of a linked list like a treasure hunt:
- Each clue contains data
- Each clue points to the next clue
You must follow the chain to reach the end.
Advantages of Linked Lists
- Dynamic size
- Efficient insertion and deletion
- No memory wastage
Mini Practice
- Create a linked list with 3 nodes
- Store integer values
- Traverse and print the list
Quick Quiz
Q1. What is a linked list?
Q2. What does each node contain?
Q3. Which function allocates memory dynamically?
Q4. Why are linked lists better than arrays?
Q5. What does the last node point to?