Algo & Program to Create and Traverse a Linked List

What is a Linked List?

A linked list is a linear data structure where each element (called a node) contains two parts:

• Data: The value stored in the node.
• Pointer (next): A reference to the next node in the list.

Unlike arrays, linked lists do not require contiguous memory locations. They allow dynamic memory allocation and efficient insertion/deletion operations.

Algorithm to Create and Traverse a Linked List

Let’s break down the process into simple steps.

Step-by-Step Algorithm

1. Creation of Linked List

1. Start
2. Define a node structure with two fields: data and pointer to the next node.
3. Create a function to insert a new node at the end:
   • Allocate memory for the new node.
   • Assign the input data to the node.
   • Set the next pointer of the node to NULL.
   • If the list is empty, make the new node the head.
   • Otherwise, traverse to the last node and update its next pointer to point to the new node.
4. Repeat the insertion as needed.

2. Traversal of Linked List

1. Start from the head node.
2. While the current node is not NULL:
   • Print the data of the current node.
   • Move to the next node.
3. End

C Program to Create and Traverse a Linked List

Here is a simple and complete C program:

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

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

// Function to create a new node
struct Node* createNode(int value) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = value;
    newNode->next = NULL;
    return newNode;
}

// Function to insert a node at the end
void insertAtEnd(struct Node** head, int value) {
    struct Node* newNode = createNode(value);
    if (*head == NULL) {
        *head = newNode;
    } else {
        struct Node* temp = *head;
        while (temp->next != NULL) {
            temp = temp->next;
        }
        temp->next = newNode;
    }
}

// Function to traverse and print the linked list
void traverseList(struct Node* head) {
    struct Node* temp = head;
    printf("Linked List: ");
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}

// Main function
int main() {
    struct Node* head = NULL;

    // Insert elements into the linked list
    insertAtEnd(&head, 10);
    insertAtEnd(&head, 20);
    insertAtEnd(&head, 30);

    // Traverse and display the linked list
    traverseList(head);

    return 0;
}

Output

Linked List: 10 -> 20 -> 30 -> NULL

Explanation

• struct Node: Defines the structure of a single node.
• createNode(): Dynamically allocates memory and initializes a new node.
• insertAtEnd(): Adds a new node at the end of the list.
• traverseList(): Starts from the head and prints each node’s value until the end.