C++ Program to Implement Queue using Linked List cpp

1. #include <bits/stdc++.h>
   using namespace std;
   
   struct QNode {
       int data;
       QNode* next;
       QNode(int d)
       {
           data = d;
           next = NULL;
       }
   };
   
   struct Queue {
       QNode *front, *rear;
       Queue() { front = rear = NULL; }
   
       void enQueue(int x)
       {
   
           // Create a new LL node
           QNode* temp = new QNode(x);
   
           // If queue is empty, then
           // new node is front and rear both
           if (rear == NULL) {
               front = rear = temp;
               return;
           }
   
           // Add the new node at
           // the end of queue and change rear
          rear->next = temp;
           rear = temp;
       }
   
       // Function to remove
       // a key from given queue q
       void deQueue()
       {
           // If queue is empty, return NULL.
           if (front == NULL)
               return;
   
           // Store previous front and
           // move front one node ahead
           QNode* temp = front;
           front = front->next;
   
           // If front becomes NULL, then
           // change rear also as NULL
           if (front == NULL)
               rear = NULL;
   
           delete (temp);
       }
   };
   
   // Driver code
   int main()
   {
   
       Queue q;
       q.enQueue(10);
       q.enQueue(20);
       q.deQueue();
       q.deQueue();
       q.enQueue(30);
       q.enQueue(40);
       q.enQueue(50);
       q.deQueue();
       cout << "Queue Front : " << ((q.front != NULL) ? (q.front)->data : -1)<< endl;
       cout << "Queue Rear : " << ((q.rear != NULL) ? (q.rear)->data : -1);
   }
   

2.