循环队列

#ifndef SEQQUEUE_H

#define SEQQUEUE_H

 

#include <iostream>

#include <assert.h>

using namespace std;

 

template<class T>

class SeqQueue

{

public:

     SeqQueue(int sz = 10);

     ~SeqQueue()

     {

         delete []elements;

     }

     bool EnQueue(const T& x);   //若队列不满，则将x进队，否则队溢出处理

     bool DeQueue(T& x);    //若队列不空，则退出队头元素x并由函数返回true，否则队空，返回false

     bool GetFront(T& x)const;   //若队列不空，则函数返回true及队头元素的值，否则返回false

     void MakeEmpty()   //置空操作，队头和队尾指针置为

     {

         front = rear = 0;

     }

     bool IsEmpty()const

     {

         return (front == rear) ? true : false;

     }

     bool IsFull()const

     {

         return ((rear + 1) % maxSize == front) ? true : false;

     }

     int GetSize()const //求队列元素的个数

     {

         return (rear - front + maxSize) % maxSize;

     }

     template<class T>

     friend ostream& operator<<(ostream& os,SeqQueue<T>& q);

private:

     int front,rear;    //队头和队尾指针

     T *elements;  //存放队元素的数组

     int maxSize;  //队列最大可容纳元素个数

};

 

template<class T>

SeqQueue<T>::SeqQueue(int sz /* = 10 */):front(0),rear(0),maxSize(sz)

{

     elements = new T[maxSize];

     assert(elements != NULL);

}

 

template<class T>

bool SeqQueue<T>::EnQueue(const T &x)

{

     if(IsFull() == true)

         return false;

     elements[rear] = x;

     rear = (rear + 1) % maxSize;     //队尾指针加

     return true;

}

 

template<class T>

bool SeqQueue<T>::DeQueue(T& x)

{

     if(IsEmpty() == true)

         return false;

     x = elements[front];

     front = (front + 1) % maxSize;

     return true;

}

 

template<class T>

bool SeqQueue<T>::GetFront(T &x)const

{

     if(IsEmpty() == true)

         return false;

     x = elements[front];

     return true;

}

 

template<class T>

ostream& operator<<(ostream& os,SeqQueue<T>& q)

{

     os<<"front="<<q.front<<",rear="<<q.rear<<endl;

     for(int i = q.front;i != q.rear;i = (i + 1) % q.maxSize)

         os<<i<<":"<<q.elements[i]<<endl;

     return os;

}

 

#endif