C++ STL queue container traversal output method

Normally we can use the class template we wrote ourselves to implement the chain queue:

/**********************************链队列的实现********************************/
template<class QElemType>
class LinkQueue;

template<class QElemType>
class QNode {
protected:
	QElemType	data;
	QNode<QElemType>	*next;
public:
	friend class LinkQueue<QElemType>;
};

template<class QElemType>
class LinkQueue {
protected:
	QNode<QElemType>	*front;
	QNode<QElemType>	*rear;
public:
	LinkQueue();
	virtual	~LinkQueue();
	Status	EnQueue(QElemType e);
	Status	DeQueue(QElemType &e);
	void	PrintQueue();
	int	QueueLength();
	Status	QueueEmpty();
};

template<class QElemType>
LinkQueue<QElemType>::LinkQueue()
{
	front = rear = new(nothrow)QNode<QElemType>;
	if (!front)
		exit(LOVERFLOW);
	front->next = nullptr;
}

template<class QElemType>
LinkQueue<QElemType>::~LinkQueue()
{
	while (front) {
		rear = front->next;
		delete front;
		front = rear;
	}
}

template<class QElemType>
Status LinkQueue<QElemType>::EnQueue(QElemType e)
{
	QNode<QElemType> *p = new(nothrow)QNode<QElemType>;
	if (!p)
		return LOVERFLOW;
	p->data = e;
	p->next = nullptr;
	rear->next = p;
	rear = p;
	return OK;
}

template<class QElemType>
Status LinkQueue<QElemType>::DeQueue(QElemType &e)
{
	QNode<QElemType> *p;
	if (front == rear)
		return ERROR;
	p = front->next;
	e = p->data;
	front->next = p->next;
	if (rear == p)
		rear = front;
	delete p;
	return OK;
}

template<class QElemType>
void LinkQueue<QElemType>::PrintQueue()
{
	QNode<QElemType> *p = front->next;
	while (p) {
		cout << p->data << ' ';
		p = p->next;
	}
	cout << endl;
}

template<class QElemType>
int LinkQueue<QElemType>::QueueLength()
{
	int i = 0;
	QNode<QElemType> *p = front->next;
	while (p) {
		i++;
		p = p->next;
	}
	return i;
}

template<class QElemType>
Status LinkQueue<QElemType>::QueueEmpty()
{
	if (front == rear)
		return TRUE;
	return FALSE;
}

However, the STL queue container that comes with C++ has a great advantage in terms of code size. As long as you add

#include <queue>

You can easily use the following functions:

queue<int> q;
q.empty();    //当队列空时，返回true
q.pop();    //弹出队列第一个元素，注意！并不会返回被弹出元素的值
q.push(x);    //将x接到队列的末尾
q.front();    //访问队首元素
q.back();    //访问队尾元素
q.size();    //访问队列中元素个数

Because the queue container does not allow direct operations on q, how should the queue traversal output be performed? I encountered such a problem yesterday when I was completing the data structure hash table. Later, I found that as long as I perform the front operation first, then pop the first element, and at the same time determine whether the queue is empty, I can achieve such a function. . The specific implementation is as follows:

while (!q.empty()) {
		cout << q.front() << " ";
		q.pop();
	}