[207Lec4]CircularQueueWithArray

#include <iostream>
#define MAX 5
using namespace std;

int Q[MAX];
int head = -1;
int tail = -1;
int count = 0;

bool isEmpty() {
    if (count == 0) return true;
    else return false;
}

bool isFull() {
    if (count == MAX) return true;
    else return false;
}

void display() {
    if (count) {
        for (int i = 0, j = head; i < count; i++, ++j %= MAX)
            cout << Q[j] << " ";
        cout << endl;
    }
    else cout << "Queue is Empty" << endl;
}

void enqueue(int x) {
    if (isFull()) {
        cout << "Cannot Enqueue " << x << endl;
        cout << "Queue is Full/OverFlow" << endl;
    }
    else {
        Q[++tail % MAX] = x;
        if (isEmpty()) head++;
        count++;
    }
    display();
}

void dequeue() {
    if (count) {
        ++head %= MAX;
        count--;
        if (isEmpty()) {
            head = -1;
            tail = -1;
        }
        display();
    }
    else {
        cout << "Cannot Dequeue" << endl;
        cout << "Queue is Empty/Underflow" << endl;
    }
}




int main() {
    int choice, value;

    while (true) {
        cout << "1. Enqueue" << endl;
        cout << "2. Dequeue" << endl;
        cout << "3. Display" << endl;
        cout << "4. Quit" << endl;
        cout << "Choice: ";
        cin >> choice;

        if (choice == 1) {
            cout << "Enter value to Enqueue: ";
            cin >> value;
            enqueue(value);
        }
        else if (choice == 2) dequeue();
        else if (choice == 3) display();
        else if (choice == 4) break;
        else cout << "Invalid Choice" << endl;

        cout << endl;
    }
    return 0;
}