Lab Cycle 2 — Stack & Queue

#include <iostream>
using namespace std;

struct Node { int data; Node* next; };
Node* front = NULL, *rear = NULL;

void enqueue(int val) {
    Node* newNode = new Node();
    newNode->data = val;
    newNode->next = NULL;
    if (rear == NULL) front = rear = newNode;
    else { rear->next = newNode; rear = newNode; }
}

void dequeue() {
    if (front == NULL) { cout << "Queue Empty\n"; return; }
    Node* temp = front;
    front = front->next;
    if (front == NULL) rear = NULL;
    delete temp;
}

int main() {
    enqueue(10); enqueue(20); enqueue(30);
    dequeue();
    return 0;
}