data structure --Queue(基于数组的实现)-蒲公英云

data structure --Queue(基于数组的实现)

#include<iostream>
using namespace std;
const int maxqueue=10;
template <class T>
class ArrayQueue
{
public:
    ArrayQueue();
    bool empty() const; 
    bool full() const;
    int size() const;
    void append(T &item);
    void serve();
    T& retrieve();
    void clear();
private:
    int count;
    int front,rear;
    T array[maxqueue];        
};
template <class T>
ArrayQueue<T>::ArrayQueue()
/*Pre: None
  Post: The Queue is initialized to be empty.*/
{
    count=0;
    front=0;
    rear=maxqueue-1;
}
template <class T>
bool ArrayQueue<T>::empty() const
/*Pre: None
  Post: Return true if the Queue is empty,otherwise return false.*/
{
    return count==0;
}
template <class T>
bool ArrayQueue<T>::full() const
/*Pre:None
  Post:If the queue is full,true is returned.Otherwise,false is returned*/
{
    return count==10;
}
template <class T>
int ArrayQueue<T>::size() const
/*Pre:None
  Post:Return the number of entries in the queue.*/
{
    return count;
}
template <class T>
void ArrayQueue<T>::append(T &item)
/*Pre: None
  Post: Item is added to the rear of the Queue if it is not full,otherwise the queue is left unchanged.*/
{
    if(count<maxqueue)
    {
         count++;
         rear=((rear+1)==maxqueue)?0:(rear+1);
         array[rear]=item;
    }      
}
template <class T>
void ArrayQueue<T>::serve()
/*Pre: None
  Post: The front of the Queue  is removed if the queue is not empty.*/
{
    if(count>0)
    {
        count--;
        front=((front+1)==maxqueue)?0:(front+1);
    }
}
template <class T>
T& ArrayQueue<T>::retrieve()
/*Pre: None
  Post: The front of the Queue  is returnd if the queue is not empty.*/
{
    if(count>0)
       return array[front];
}
template <class T>
void ArrayQueue<T>::clear()
/*Pre: None
  Post: The Queue  is reset to be empty.*/
{
    count=0;
    front=0;
    rear=maxqueue-1;
}