#include"clist.h"
#include"listIterator.h"
template<class T>
  class doubleEndList:public list<T>
{
public:
//構(gòu)造函數(shù)
doubleEndList();
doubleEndList(const doubleEndList<T>& v);
//遮蔽表類中原有操作
virtual void add(T value);
virtual void deleteAllValue();
virtual void removeFirst();
//增加新的操作
void addToEnd(T value);
protected:
//增加新的數(shù)據(jù)域
link<T>*ptrToLastLink;
};

template<class T>doubleEndList<T>::add(T val)
{
if(isEmpty())
{
	list<T>::add(val);
ptrToLastLink=ptrToFirstLink;
}
else
list<T>::add(val);
}
template<class T>void doubleEndList<T>::addToEnd(T val)
{
if(ptrToLastLink!=0)
ptrToLastLink=ptrToLastLink->insert(val);
else 
add(val);
}

template<class T>
doubleEndList<T>::doubleEndList(const doubleEndList<T>&v)
:clist<T>(){
	if(!v.isEmpty()){
listIterator<term>itr(v);
for(itr.init();!itr;++itr)
addToEnd(itr());
}
else
ptrToFirstLink=0;
}

template<class T>
doubleEndList<T>::deleteAllValues()
{
	clist<T>::deleteAllValues();
	ptrToLastLink=0;
}

template<class T>
doubleEndList<T>::removeFirst()
{
	clist<T>::removeFirst();
	if(clist<T>::isEmpty())
ptrToLastLink=0;
}