Create a new node with the given value and set its next pointer to NULL.
Initialize a temporary pointer to the head of the linked list for traversal.
Traverse the list using the temporary pointer until reaching the last node.
Point the next pointer of the last node to the newly created node, making it the new tail of the linked list.
Return the head of the linked list to get the updated list.

Code

#include <bits/stdc++.h>
using namespace std;

// Definition of singly linked list
struct ListNode
{
    int val;
    ListNode *next;
    ListNode(int data1)
    {
        val = data1;
        next = NULL;
    }
    ListNode(int data1, ListNode *next1)
    {
        val = data1;
        next = next1;
    }
};

// Solution class
class Solution {
public:
    // Function to insert a new node at the tail of the linked list
    ListNode* insertAtTail(ListNode* &head, int X) {
        if (head == NULL)
            return new ListNode(X);

        ListNode* temp = head;
        // Traversing until the last node
        while (temp->next != NULL) {
            temp = temp->next;
        }
        
        ListNode* newNode = new ListNode(X);
        temp->next = newNode;

        return head;
    }
};

// Helper Function to print the linked list
void printLL(ListNode* head) {
    while (head != NULL) {
        cout << head->val << " ";
        head = head->next;
    }
    cout << endl;
}

int main() {
    // Create a linked lis