Singly link list traversal

In today’s blog we are going to see how we can make singly link list in any language today we will see how we can make it in C.

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Creation of Node:

• As we know Link list contain the data in the form of NODE so first, we will create node.

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

• Here node will contain 2 things that are data and address of next node.

• So, the first entry we will take is of data and the next entry will be of address of next node.

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Insertion of data

• Now after creating the node, we will have to add data in front of the link list.

The complete code for insertion of node is-

void insert(struct Node** head, int newData) {
    // Allocate memory for new node
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    // Set data for the new node
    newNode->data = newData;
    // Set next of new node as head
    newNode->next = *head;
    // Move the head to point to the new node
    *head = newNode;
}

• In this code we are inserting of the data for that we will use FUNCTIONS.

• The newData value (passed to the function) is assigned to the data field of the new node.

• The next field of the new node is set to the current head of the list.

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Printing the link list

We will make a function so that we can call the function when we require to print the data.

void printList(struct Node* head) {
    struct Node* temp = head;

    // Traverse the list and print each node
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}

• struct Node* head This is a pointer to the head of the linked list.

• A temporary pointer temp is initialized to point to the head of the list.

• This loop continues as long as temp is not NULL, meaning we have not reached the end of the list.

• For each node, the data field is printed followed by an arrow (->) to visually indicate the link between nodes.

• temp is updated to point to the next node in the list (temp->next), moving the traversal forward.

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Main function

This is the main function where we will write the main part and without it we cant do anything in our code.

int main() {
    // Initialize an empty linked list
    struct Node* head = NULL;

    // Insert nodes at the beginning
    insertAtBeginning(&head, 5);
    insertAtBeginning(&head, 10);
    insertAtBeginning(&head, 15);

    // Print the linked list
    printf("Linked List: ");
    printList(head);

    return 0;
}

• We declare a pointer head that will point to the first node of the linked list.

• Initially, the list is empty, so head is set to NULL.

• We call the insertAtBeginning function three times to insert three nodes at the beginning of the list.

• The data values 5, 10, and 15 are inserted, with 15 being the first element after all insertions.

• The printList function is called to print the contents of the list.

• The final list will look like 15 -> 10 -> 5 -> NULL.

The complete code for the link list is as follows-

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

// Define a node structure
struct Node {
    int data;
    struct Node* next;
};

// Function to insert a new node at the beginning of the list
void insertAtBeginning(struct Node** head, int newData) {
    // Allocate memory for new node
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));

    // Set data for the new node
    newNode->data = newData;

    // Set next of new node as head
    newNode->next = *head;

    // Move the head to point to the new node
    *head = newNode;
}

// Function to print all nodes in the linked list
void printList(struct Node* head) {
    struct Node* temp = head;

    // Traverse the list and print each node
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}

// Main function to demonstrate the linked list operations
int main() {
    // Initialize an empty linked list
    struct Node* head = NULL;

    // Insert nodes at the beginning
    insertAtBeginning(&head, 5);
    insertAtBeginning(&head, 10);
    insertAtBeginning(&head, 15);

    // Print the linked list
    printf("Linked List: ");
    printList(head);
    return 0;
}

In this way we can write our first code of link list.

Don’t forget to use comments to increase understanding of code for the viewer.