Creating a Singly Linked List from Scratch in DSA C - Code It Step by Step

Creating a Singly Linked List from Scratch

📖 Scenario: Imagine you want to keep a list of your favorite fruits in order. You want to add fruits one by one and see the list grow. A singly linked list is a simple way to do this, where each fruit points to the next one.

🎯 Goal: You will build a singly linked list in C from scratch. You will create nodes, link them, and print the list to see all fruits in order.

📋 What You'll Learn

Define a struct for a node with a string and a pointer to the next node

Create three nodes with the fruits: "Apple", "Banana", and "Cherry"

Link the nodes to form a list: Apple -> Banana -> Cherry -> NULL

Print the list showing each fruit followed by an arrow, ending with NULL

💡 Why This Matters

🌍 Real World

Linked lists are used in many programs to manage lists of items where size can change, like playlists, task lists, or undo history.

💼 Career

Understanding linked lists is fundamental for software developers, especially when working with low-level data structures or preparing for technical interviews.

1

Define the Node Structure and Create the First Node

Define a struct called Node with a char* called data and a pointer to Node called next. Then create a variable called head of type Node* and assign it a new node with data set to "Apple" and next set to NULL.

DSA C

#include 
#include 

// Define the Node struct and create the head node
// Your code here

Hint

Use typedef struct Node to define the node. Use malloc to create the first node and set its data and next.

2

Create Two More Nodes and Link Them

Create two more Node* variables called second and third. Assign each a new node with data set to "Banana" and "Cherry" respectively, and next set to NULL. Then link the nodes by setting head->next to second and second->next to third.

DSA C

#include 
#include 

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

int main() {
    Node* head = (Node*)malloc(sizeof(Node));
    head->data = "Apple";
    head->next = NULL;

    // Create second and third nodes and link them
    // Your code here

    return 0;
}

Hint

Use malloc to create second and third nodes. Set their data and next. Link them by setting head->next and second->next.

3

Write a Loop to Print the Linked List

Create a Node* variable called current and set it to head. Use a while loop that runs while current is not NULL. Inside the loop, print current->data followed by " -> ". Then update current to current->next. After the loop, print "NULL\n".

DSA C

#include 
#include 

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

int main() {
    Node* head = (Node*)malloc(sizeof(Node));
    head->data = "Apple";
    head->next = NULL;

    Node* second = (Node*)malloc(sizeof(Node));
    second->data = "Banana";
    second->next = NULL;

    Node* third = (Node*)malloc(sizeof(Node));
    third->data = "Cherry";
    third->next = NULL;

    head->next = second;
    second->next = third;

    // Print the linked list
    // Your code here

    return 0;
}

Hint

Use a while loop with current to go through the list. Print each node's data and then move to the next node.

4

Print the Final Linked List Output

Add a printf statement to print the entire linked list in the format: Apple -> Banana -> Cherry -> NULL by running the loop you wrote.

DSA C

#include 
#include 

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

int main() {
    Node* head = (Node*)malloc(sizeof(Node));
    head->data = "Apple";
    head->next = NULL;

    Node* second = (Node*)malloc(sizeof(Node));
    second->data = "Banana";
    second->next = NULL;

    Node* third = (Node*)malloc(sizeof(Node));
    third->data = "Cherry";
    third->next = NULL;

    head->next = second;
    second->next = third;

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

    return 0;

    // Your code here
}

Hint

Run the program to see the linked list printed as Apple -> Banana -> Cherry -> NULL.