循环队列的C++实现

文章选自

https://www.cnblogs.com/diegodu/p/4619104.html

https://blog.csdn.net/alidada_blog/article/details/80313388

循环队列初始条件:队头指针（front）=队尾指针(rear)=0
循环队列队满条件:(rear+1)%size == front (size是顺序表的最大储存空间)
循环队列空条件:队头指针（rear）=队尾指针(front)

队头指针向后移动计算:队头指针= (rear+1)%size (size是顺序表的最大储存空间)
队尾指针向后移动计算:队尾指针= (front+1)%size (size是顺序表的最大储存空间)

空队时指针（下标）front和rear在一起都指向队前方，当有元素进队，则rear后移；有元素出队，则front后移，最后，开始时分配给队的前端不再被利用。

注意：空队时rear等于front，满队时必须空一个位置

#include <iostream>

using namespace std;

template <class T>
class cycleQueue
{
    private: 
        unsigned int m_size;
        int m_front;
        int m_rear;
        T*  m_data;
    public:
        cycleQueue(unsigned size):m_size(size),m_front(0),m_rear(0)
        {   
            m_data = new T[size];
        }   

        ~cycleQueue()
        {   
            delete []m_data;
        }   

        bool isEmpty()
        {   
            return m_front == m_rear;
        }   

        bool isFull() 
        {   
            return m_front == (m_rear + 1)%m_size;
        }   

        void push(T ele)throw(bad_exception)
        {
            if(isFull())
            {
                throw bad_exception();
            }
            m_data[m_rear] = ele;
            m_rear = (m_rear + 1)%m_size;
        }

        T pop() throw(bad_exception)
        {
            if(isEmpty())
            {
                throw bad_exception();
            }
            T tmp = m_data[m_front];
            m_front = (m_front + 1)%m_size;
            return tmp;
        }
};


int main()
{
    cycleQueue<int> q(5);
    q.push(1);
    q.push(2);
    q.push(3);
    q.push(4);
    for (int i = 0; i < 4 ; i++)
        cout << q.pop() << endl;
    q.push(5);
    q.push(5);
    q.push(5);
    cout << q.pop() << endl;
    cout << q.pop() << endl;
    cout << q.pop() << endl;
    cout << q.pop() << endl;
    return 0;
}