自己写了类实现了deque的功能，还行吧！
用了函数模板了。

STL中dpque的函数↓：

完整代码：

#include<iostream>
using namespace std;
const int MaxSize = 60;//队列容量

template <typename T>
class Deque {
private:
	T data[MaxSize];
	int front, rear, count;
public:
	Deque() {
		this->front = 0;
		this->rear = 0;
		this->count = 0;
	}
	bool push_front(T x)
	{
		if ((rear + 1) % MaxSize == front) return false;
		data[front] = x;//元素e进队
		front = (front - 1 + MaxSize) % MaxSize;
		count++;
		return true;
	}
	bool push_back(T x)
	{
		if (count == MaxSize) return false;
		else {
			rear = (rear + 1) % MaxSize;
			data[rear] = x;
			count++;
			return true;
		}//else
	}
	T pop_front()
	{
		if (count == 0) return 1;
		else {
			front = (front + 1) % MaxSize;
			count--;
			return data[front];
		}//else
	}
	T pop_back()
	{
		if (count == 0) return -1;
		T x;
		x = data[rear];//提取队尾元素
		rear = (rear - 1 + MaxSize) % MaxSize;
		count--;
		return x;
	}
};

int main()
{
	Deque<int> q;
	q.push_front(2);
	cout << q.pop_back() << endl;
	q.push_front(3);
	q.push_back(4);
	cout << q.pop_front() << endl;
	return 0;
}