//Stack
#include<bits/stdc++.h>

using namespace std;

#define MAX 1000

class Stack
{
    int top;
public:
    int a[MAX];

    Stack() { top = -1; }
    bool push(int x);
    int pop();
    bool isEmpty();
};

bool Stack::push(int x)
{
    if (top >= (MAX-1))
    {
        cout << "Stack Overflow";
        return false;
    }
    else
    {
        a[++top] = x;
        cout<<x <<" pushed into stack\n";
        return true;
    }
}

int Stack::pop()
{
    if (top < 0)
    {
        cout << "Stack Underflow";
        return 0;
    }
    else
    {
        int x = a[top--];
        return x;
    }
}

bool Stack::isEmpty()
{
    return (top < 0);
}

int main()
{
    class Stack s;
    s.push(10);
    s.push(20);
    s.push(30);
    cout<< "-------------------\n";
    cout<<s.pop() << " Popped from stack\n";
    cout<<s.pop() << " Popped from stack\n";
    cout<<s.pop() << " Popped from stack\n";
    cout<<s.pop() << " Popped from stack\n";

    return 0;
}

QUEUE:

#include <iostream>
#define SIZE 5

using namespace std;

class Queue {
    int items[SIZE], front, rear;

public:
    Queue(){
        front = -1;
        rear = -1;
    }

    bool isFull();
    bool isEmpty();
    void enQueue(int element);
    int deQueue();
    void display();

};

bool Queue::isFull(){
        if(front == 0 && rear == SIZE - 1){
            return true;
        }
        if(front == rear + 1) {
            return true;
        }
        return false;
    }

bool Queue::isEmpty(){
        if(front == -1)
            return true;
        else
            return false;
}
void Queue::enQueue(int element){
        if(isFull()){
            cout << "\nQueue is full\n---------------" << endl;
        } else {
            if(front == -1) front = 0;
            rear = (rear + 1) % SIZE;
            items[rear] = element;
            cout << endl << "-------------\nInserted " << element << endl;
        }
}


int Queue::deQueue(){
        int element;
        if(isEmpty()){
            cout << "Queue is empty" << endl;
            return(-1);
        } else {
            element = items[front];
            if(front == rear){
                front = -1;
                rear = -1;
            } /* Q has only one element, so we reset the queue after deleting it. */
            else {
                front=(front+1) % SIZE;
            }
            return(element);
        }
    }

void Queue::display(){
        int i;
        if(isEmpty()) {
            cout << endl << "Empty Queue" << endl;
        }
        else
        {
            cout << "\nFront -> " << front;
            cout << endl << "Items -> ";
            for(i=front; i!=rear;i=(i+1)%SIZE)
                cout << items[i] <<" ";
            cout << items[i];
            cout << endl << "Rear -> " << rear;
        }
    }



int main()
{
    Queue q;

    q.deQueue();

    q.enQueue(1);
    q.display();
    q.enQueue(2);
    q.display();
    q.enQueue(3);
    q.display();
    q.enQueue(4);
    q.display();
    q.enQueue(5);
    q.display();

    q.enQueue(6);
    q.display();

    int elem = q.deQueue();
    if( elem != -1)
       cout << endl << "Deleted Element is " << elem;

    q.display();
    q.enQueue(7);
    q.display();
    q.enQueue(8);

    return 0;
}