スタックベースの優先キューの実装

#ifndef PQUEUEEXCEPTION_H_
#define PQUEUEEXCEPTION_H_
#include<stdexcept>
#include<string>
class PQueueException :public std::logic_error
{
	public:
		PQueueException(const std::string &message="")
			:std::logic_error(message.c_str())
		{}
};
#endif

#ifndef PRIORITYQUEUE_H_
#define PRIORITYQUEUE_H_
#include"heap_array.h"
#include"PQueueexception.h"
typedef HeapItemType PQueueItemType;
class PriorityQueue
{
	public:
		PriorityQueue();
		//default constructor ,copy constructor and 
		//destrutor are supplied by the complier

		//priority-queue operations:
		virtual bool pqempty()const;
		virtual void pqInsert(const PQueueItemType &newitem)
			throw(PQueueException);
		virtual void pqDelete(PQueueItemType &rootitem)
			throw(PQueueException);
	private:
		Heap h;
};
#endif

#include"priorityQueue.h"
PriorityQueue::PriorityQueue()
	:h()
{}
bool PriorityQueue::pqempty()const
{
	return h.empty();
}
void PriorityQueue::pqInsert(const PQueueItemType &newitem)
	throw(PQueueException)
{
	try{
		h.heapInsert(newitem);
	}
	catch(HeapException &e)
	{
		throw PQueueException("PQueueException : insert item failed !");
	}
}
void PriorityQueue::pqDelete(PQueueItemType &rootitem)
	throw(PQueueException)
{
	try{
		h.heapDelete(rootitem);
	}catch(PQueueException &e)
	{
		throw PQueueException("PQueueException :delete item failed !");
	}
}

#include<iostream>
#include"priorityQueue.h"
using namespace std;
int main()
{
	PriorityQueue apq;

	try{
	apq.pqInsert(KeyItem("sort"));
	apq.pqInsert(KeyItem("exception"));
	apq.pqInsert(KeyItem("STL"));
	apq.pqInsert(KeyItem("queue"));
	apq.pqInsert(KeyItem("priority"));
	apq.pqInsert(KeyItem("heap"));
	apq.pqInsert(KeyItem("item"));
	apq.pqInsert(KeyItem("terrda"));
	apq.pqInsert(KeyItem("absort"));
	apq.heapInsert(KeyItem("oppo"));
//	aheap.display();
	KeyItem item;
	cout<<"the priority queue is :"<<endl;
	while(!apq.empty())
	{
		apq.pqDelete(item);
		cout<<item.getKey()<<endl;
	}
	}catch(PQueueException &e)
	{
		cout<<e.what()<<endl;
	}
	return 0;
}