Insert at End Tail Insert in DSA C - Build from Scratch

Insert at End Tail Insert in a Linked List

📖 Scenario: Imagine you are managing a line of people waiting to buy tickets. Each person joins the end of the line. We will represent this line using a linked list, where each node is a person.

🎯 Goal: You will build a simple linked list in C and learn how to add a new person (node) at the end of the line (tail insert).

📋 What You'll Learn

Create a linked list node structure with an integer data field and a next pointer

Create an initial linked list with two nodes having values 10 and 20

Create a function to insert a new node at the end of the linked list

Insert a new node with value 30 at the end

Print the linked list to show the final order

💡 Why This Matters

🌍 Real World

Linked lists are used in many applications like managing playlists, undo functionality in editors, and dynamic memory allocation.

💼 Career

Understanding linked lists and how to insert nodes is fundamental for software developers working with data structures and system programming.

1

Create the initial linked list with two nodes

Create a struct called Node with an int data and a Node* next. Then create two nodes called head and second. Set head->data to 10, second->data to 20, and link head->next to second. Set second->next to NULL.

DSA C

# Define struct Node and create two nodes head and second
# Your code here

Hint

Remember to use malloc to create nodes and link them by setting the next pointer.

2

Create a function to insert a node at the end

Create a function called insertAtEnd that takes Node** head and int data. Inside, create a new node with data and next as NULL. If the list is empty (*head == NULL), set *head to the new node. Otherwise, traverse the list using a Node* temp until temp->next == NULL, then set temp->next to the new node.

DSA C

#include 
#include 

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

// Define insertAtEnd function here
# Your code here

int main() {
    Node* head = (Node*)malloc(sizeof(Node));
    Node* second = (Node*)malloc(sizeof(Node));

    head->data = 10;
    head->next = second;

    second->data = 20;
    second->next = NULL;

    return 0;
}

Hint

Use a double pointer Node** head to modify the head pointer if the list is empty.

3

Insert a new node with value 30 at the end

Call the function insertAtEnd with the address of head and the value 30 to add a new node at the end of the list.

DSA C

#include 
#include 

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

void insertAtEnd(Node** head, int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = NULL;

    if (*head == NULL) {
        *head = newNode;
        return;
    }

    Node* temp = *head;
    while (temp->next != NULL) {
        temp = temp->next;
    }
    temp->next = newNode;
}

int main() {
    Node* head = (Node*)malloc(sizeof(Node));
    Node* second = (Node*)malloc(sizeof(Node));

    head->data = 10;
    head->next = second;

    second->data = 20;
    second->next = NULL;

    // Insert new node with data 30 at the end
    # Your code here

    return 0;
}

Hint

Call insertAtEnd with &head and 30 inside main.

4

Print the linked list to show the final order

Create a Node* variable called temp and set it to head. Use a while loop to traverse the list while temp != NULL. Inside the loop, print temp->data followed by -> . Move temp to temp->next. After the loop, print NULL.

DSA C

Hint

Use a while loop to print each node's data followed by -> , then print NULL at the end.