Double ended queue in cpp

	#include< iostream > using namespace std;
	int queue[1001], front = 0, rear = 0;
	void enqueueBack(int element, int n)
	{
	if(rear != n) {
	queue[rear] = element;
	rear++;
	}
	}
	void enqueueFront(int element, int n)
	{
	if(rear != n) {
	for(int i = rear; i > front; i--) {
	queue[i] = queue[i-1];
	}
	queue[front] = element;
	rear++;
	}
	}
	void dequeueBack()
	{
	if(front != rear) {
	queue[--rear] = 0;
	}
	}
	void dequeueFront()
	{
	if(front != rear){
	queue[front++] = 0;
	}
	}
	int get_front()
	{
	return queue[front];
	}
	int get_back()
	{
	return queue[rear-1];
	}
	int size()
	{
	return rear - front;
	}
	bool isEmpty()
	{
	return front == rear;
	}
	int main()
	{
	int n, k, m;
	cin >> n >> m;
	for(int i = 0; i < n; i++) {
	cin >> k;
	enqueueFront(k, n);
	}
	cout << "Queue element are :";
	for(int i = 0; i < n; i++) cout << queue[i] << " ";
	cout << endl;
	for(int i = 0; i < m; i++) {
	cin >> k;
	enqueueBack(k,n+m);
	}
	cout << "Queue element are :";
	for(int i = 0; i < n+m ; i++) cout << queue[i] << " ";
	cout << endl;
	cout <<"Queue size :" << size() << endl;
	cout << "Queue is empty = " << (isEmpty()? "True":"False") << endl;
	cout << "Queue front element = " << get_front() << endl;
	cout << "Queue back element = " << get_back() << endl;
	dequeueFront();
	dequeueBack();
	cout << "Queue new front element = " << get_front() << endl;
	cout << "Queue new back element = " << get_back() << endl;
	cout <<"Queue new size :" << size() << endl;
	return 0;
	}

Implement queue using two stack in cpp

	#include< iostream > #include< stack >
	using namespace std;
	stack<int> s1, s2;
	void enqueue(int data)
	{
	while(!s1.empty()) {
	s2.push(s1.top());
	s1.pop();
	}
	s1.push(data);
	while(!s2.empty()) {
	s1.push(s2.top());
	s2.pop();
	}
	}
	void dequeue()
	{
	if(!s1.empty()) {
	s1.pop();
	}
	}
	int front()
	{
	return s1.top();
	}
	bool isEmpty()
	{
	return s1.size() == 0;
	}
	int size()
	{
	return s1.size();
	}
	void printData()
	{
	while(!s1.empty()) {
	cout << s1.top() << " ";
	s1.pop();
	}
	cout << endl;
	}
	int main()
	{
	int n, m, k;
	cin >> n;
	for(int i = 0; i < n; i++) {
	cin >> k;
	enqueue(k);
	}
	cout << "Queue is empty : " << (isEmpty()?"True":"False") << endl;
	cout << "Queue front element : " << front() << endl;
	dequeue();
	cout << "Queue size : " << size() << endl;
	enqueue(12);
	enqueue(6);
	cout << "Queue new size : " << size() << endl;
	cout << "Queue new element are : ";
	printData();
	cout << "Queue is empty : " << (isEmpty()?"True":"False") << endl;
	return 0;
	}