Why Doubly Linked List Over Singly Linked List in DSA C - See It Work

Why Doubly Linked List Over Singly Linked List

📖 Scenario: Imagine you are managing a playlist of songs where you want to move forward and backward easily between songs.A singly linked list lets you move forward only, but a doubly linked list lets you move both forward and backward.

🎯 Goal: You will create a simple doubly linked list with three songs, then show how to move forward and backward through the list.

📋 What You'll Learn

Create a doubly linked list node structure with data, next, and prev pointers

Create three nodes with song names: "Song1", "Song2", "Song3"

Link the nodes to form a doubly linked list

Traverse the list forward and print the song names

Traverse the list backward and print the song names

💡 Why This Matters

🌍 Real World

Doubly linked lists are used in music players, web browsers (back and forward buttons), and undo-redo features where moving both ways is needed.

💼 Career

Understanding doubly linked lists helps in software development roles that involve data structure design, memory management, and building efficient navigation systems.

1

Create doubly linked list nodes with song names

Define a struct called Node with char *data, Node *next, and Node *prev. Then create three nodes called node1, node2, and node3 with data set to "Song1", "Song2", and "Song3" respectively.

DSA C

// Define struct Node and create node1, node2, node3 with data
// Your code here

Hint

Remember to include next and prev pointers in the struct for doubly linked list nodes.

2

Link the nodes to form a doubly linked list

Link node1 to node2 and node2 to node3 by setting their next and prev pointers correctly to form a doubly linked list.

DSA C

#include 
#include 

typedef struct Node {
    char *data;
    struct Node *next;
    struct Node *prev;
} Node;

int main() {
    Node node1, node2, node3;
    node1.data = "Song1";
    node2.data = "Song2";
    node3.data = "Song3";

    // Link nodes to form doubly linked list
    // Your code here

    return 0;
}

Hint

Set next of a node to the next node's address and prev to the previous node's address. The first node's prev and last node's next are NULL.

3

Traverse the list forward and backward

Create a pointer current starting at &node1. Use a while loop to move forward using current->next and print each node's data. Then move backward from the last node using current->prev and print each node's data.

DSA C

#include 
#include 

typedef struct Node {
    char *data;
    struct Node *next;
    struct Node *prev;
} Node;

int main() {
    Node node1, node2, node3;
    node1.data = "Song1";
    node2.data = "Song2";
    node3.data = "Song3";

    node1.next = &node2;
    node1.prev = NULL;

    node2.next = &node3;
    node2.prev = &node1;

    node3.next = NULL;
    node3.prev = &node2;

    // Traverse forward and backward
    // Your code here

    return 0;
}

Hint

Use one loop to go forward until current->next is NULL, then another loop to go backward until current is NULL.

4

Print the traversal results

Print the song names during forward and backward traversal exactly as shown in the code. The output should first list songs forward, then backward.

DSA C

#include 
#include 

typedef struct Node {
    char *data;
    struct Node *next;
    struct Node *prev;
} Node;

int main() {
    Node node1, node2, node3;
    node1.data = "Song1";
    node2.data = "Song2";
    node3.data = "Song3";

    node1.next = &node2;
    node1.prev = NULL;

    node2.next = &node3;
    node2.prev = &node1;

    node3.next = NULL;
    node3.prev = &node2;

    Node *current = &node1;
    printf("Forward traversal:\n");
    while (current != NULL) {
        printf("%s\n", current->data);
        if (current->next == NULL) {
            break;
        }
        current = current->next;
    }

    printf("Backward traversal:\n");
    while (current != NULL) {
        printf("%s\n", current->data);
        current = current->prev;
    }

    return 0;

    // Your code here
}

Hint

Run the program and check that the output matches the forward and backward song lists exactly.