Queue implementation using stack (array).cpp

#include <iostream>
using namespace std;

const int n = 5;
int A[n] = {0}, B[n] = {0}, front = -1, rear = front;

int full(){
    return (rear >= n-1);
}

int empty(){
    return (front == -1 || rear == -1);
}

void push(int data){
    if(full()){
        cout << "[QUEUE IS FULL]! Element [" << data << "] not pushed into queue." << endl;
    } else {
        rear = (front == -1) ? ++front : ++rear;
        A[rear] = data;
    }
}

void pop(){
    if(empty()){
        cout << "[QUEUE IS EMPTY]! No element popped." << endl;
    } else if(front == rear){
        front = rear = -1;
    } else {
        int temp = -1;
        while(!empty()){ // Pop-out from the array A to B
            B[++temp] = A[rear--];
        }
        temp--; // Pop-out from the B
        while(temp >= 0){ // Pop-out elements from the array B to A
            A[++rear] = B[temp--];
        }
    }
}

void print(){
    if(empty()){
        cout << "[EMPTY QUEUE]" << endl;
    } else {
        while(!empty()){
            cout << A[front];
            pop();
            if(!empty()) cout << " <= ";
        }
        cout << endl;
    }
}

int main(){
    push(5);
    push(10);
    push(15);
    push(20);
    push(25);

    pop();
    pop();

    print();
}