#include <iostream>
using namespace std;

#define MAX_SIZE 100

class Queue {
private:
    int arr[MAX_SIZE];
    int front, rear;

public:
    Queue() {
        front = -1; // Initialize front of the queue
        rear = -1;  // Initialize rear of the queue
    }

    // Function to check if the queue is empty
    bool isEmpty() {
        return front == -1 && rear == -1;
    }

    // Function to check if the queue is full
    bool isFull() {
        return rear == MAX_SIZE - 1;
    }

    // Function to enqueue an element into the queue
    void enqueue(int value) {
        if (isFull()) {
            cout << "Queue Overflow!" << endl;
            return;
        }
        if (isEmpty()) {
            front = rear = 0;
        } else {
            rear++;
        }
        arr[rear] = value;
        cout << "Enqueued " << value << " into the queue." << endl;
    }

    // Function to dequeue an element from the queue
    int dequeue() {
        if (isEmpty()) {
            cout << "Queue Underflow!" << endl;
            return -1; // Return a default value indicating failure
        }
        int value = arr[front];
        if (front == rear) {
            front = rear = -1;
        } else {
            front++;
        }
        cout << "Dequeued " << value << " from the queue." << endl;
        return value;
    }

    // Function to return the front element of the queue without removing it
    int peek() {
        if (isEmpty()) {
            cout << "Queue is empty." << endl;
            return -1; // Return a default value indicating failure
        }
        return arr[front];
    }

    // Function to display all elements of the queue
    void display() {
        if (isEmpty()) {
            cout << "Queue is empty." << endl;
            return;
        }
        cout << "Queue elements: ";
        for (int i = front; i <= rear; ++i) {
            cout << arr[i] << " ";
        }
        cout << endl;
    }
};

int main() {
    Queue queue;
    int choice, value;

    while (true) {
        cout << "\nQueue Operations:" << endl;
        cout << "1. Enqueue" << endl;
        cout << "2. Dequeue" << endl;
        cout << "3. Peek" << endl;
        cout << "4. Display" << endl;
        cout << "5. Exit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;

        switch (choice) {
            case 1:
                cout << "Enter value to enqueue: ";
                cin >> value;
                queue.enqueue(value);
                break;
            case 2:
                queue.dequeue();
                break;
            case 3:
                cout << "Front element: " << queue.peek() << endl;
                break;
            case 4:
                queue.display();
                break;
            case 5:
                cout << "Exiting program." << endl;
                return 0;
            default:
                cout << "Invalid choice! Please try again." << endl;
        }
    }

    return 0;
}