Circular vs Linear Linked List Key Difference in DSA C - Build Both Approaches

Circular vs Linear Linked List Key Difference

📖 Scenario: Imagine you are managing a playlist of songs. You want to see how the playlist behaves differently if it loops back to the start after the last song (circular) or just ends (linear).

🎯 Goal: You will create two linked lists: one linear and one circular. You will then print their elements to see the key difference in how they behave.

📋 What You'll Learn

Create a linear linked list with nodes containing values 1, 2, 3

Create a circular linked list with nodes containing values 1, 2, 3

Traverse and print the linear linked list nodes

Traverse and print the circular linked list nodes stopping after one full cycle

💡 Why This Matters

🌍 Real World

Circular linked lists are used in applications like music playlists, round-robin scheduling, and buffering where looping back to the start is needed.

💼 Career

Understanding linked list types helps in system programming, game development, and designing efficient data structures for real-time applications.

1

Create a linear linked list with nodes 1, 2, 3

Create a struct called Node with an int data and a Node* next. Then create three nodes with values 1, 2, and 3 linked linearly (last node's next is NULL). Store the head node in a variable called linear_head.

DSA C

#include 
#include 

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

int main() {
    // Create three nodes and link them linearly
    // Your code here
    return 0;
}

Hint

Remember to allocate memory for each node using malloc and link them by setting the next pointer.

2

Create a circular linked list with nodes 1, 2, 3

Using the same Node struct, create three nodes with values 1, 2, and 3 linked circularly (last node's next points back to the first node). Store the head node in a variable called circular_head.

DSA C

#include 
#include 

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

int main() {
    struct Node* linear_head = malloc(sizeof(struct Node));
    struct Node* second = malloc(sizeof(struct Node));
    struct Node* third = malloc(sizeof(struct Node));

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

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

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

    // Create circular linked list nodes and link them circularly
    // Your code here
    return 0;
}

Hint

Make sure the last node's next points back to the first node to form a circle.

3

Traverse and print the linear linked list

Use a struct Node* pointer called current to traverse the linear linked list starting from linear_head. Use a while loop that continues while current != NULL. Inside the loop, print the data of the current node followed by ->, then move current to the next node.

DSA C

#include 
#include 

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

int main() {
    struct Node* linear_head = malloc(sizeof(struct Node));
    struct Node* second = malloc(sizeof(struct Node));
    struct Node* third = malloc(sizeof(struct Node));

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

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

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

    struct Node* circular_head = malloc(sizeof(struct Node));
    struct Node* c_second = malloc(sizeof(struct Node));
    struct Node* c_third = malloc(sizeof(struct Node));

    circular_head->data = 1;
    circular_head->next = c_second;

    c_second->data = 2;
    c_second->next = c_third;

    c_third->data = 3;
    c_third->next = circular_head;

    // Traverse and print linear linked list
    // Your code here
    return 0;
}

Hint

Use a while loop to go through each node until you reach NULL.

4

Traverse and print the circular linked list once

Use a struct Node* pointer called current to traverse the circular linked list starting from circular_head. Use a do-while loop to print the data of each node followed by ->. Stop the loop when current points back to circular_head after the first iteration. Finally, print (back to head) to show the circular link.

DSA C

#include 
#include 

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

int main() {
    struct Node* linear_head = malloc(sizeof(struct Node));
    struct Node* second = malloc(sizeof(struct Node));
    struct Node* third = malloc(sizeof(struct Node));

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

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

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

    struct Node* circular_head = malloc(sizeof(struct Node));
    struct Node* c_second = malloc(sizeof(struct Node));
    struct Node* c_third = malloc(sizeof(struct Node));

    circular_head->data = 1;
    circular_head->next = c_second;

    c_second->data = 2;
    c_second->next = c_third;

    c_third->data = 3;
    c_third->next = circular_head;

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

    // Traverse and print circular linked list once
    // Your code here
    return 0;
}

Hint

Use a do-while loop to ensure the circular list prints all nodes once and stops when it reaches the head again.