#include<iostream>
#include<deque>
using namespace std;

int main() {

	/* Create a deque */
	deque<int> data;

	/* Enqueue data into the front of queue */
	data.push_front(20);
	data.push_front(10);

	/* Enqueue data into the back of queue */
	data.push_back(30);
	data.push_back(40);
	
	cout << "Queue size: " << data.size() << endl;
	cout << "Data on top of the queue: " << data.front() << endl;
	cout << "Data on bottom of the queue: " << data.back() << endl;

	/* Dequeue data from the front of queue */
	data.pop_front();

	cout << "Queue size after dequeue from front: " << data.size() << endl;
	cout << "Now top data on queue: " << data.front() << endl;
	cout << "Now bottom data on queue: " << data.back() << endl;

	/* Dequeue data from the back of queue */
	data.pop_back();

	cout << "Queue size after dequeue from back: " << data.size() << endl;
	cout << "Now top data on queue: " << data.front() << endl;
	cout << "Now bottom data on queue: " << data.back() << endl;
	
	return 0;
}


          /****** Output ******/
          
Queue size: 4

Data on top of the queue: 10

Data on bottom of the queue: 40

Queue size after dequeue from front: 3

Now top data on queue: 20

Now bottom data on queue: 40

Queue size after dequeue from back: 2

Now top data on queue: 20

Now bottom data on queue: 30