llist.cpp

设计一个类库

#include"llist.h"

bool LList::insert(Record& item){
	fence->next = new Link(item, fence, fence->next);
	if( fence->next->next != NULL)
		fence->next->next->prev = fence->next;
	if( tail == fence)
		tail = fence->next;
	rightcnt++;
	return true;
}

bool LList::append(Record& item){
	tail = tail->next = new Link(item,tail,NULL);
	rightcnt++;
	return true;
}

bool LList::remove(Record& it){
	if (fence->next == NULL)
		return false;
	it = fence->next->rec;
	Link* ltemp = fence->next;
	if( ltemp->next != NULL)
		ltemp->next->prev = fence;
	else tail = fence;
	fence->next = ltemp->next;
	delete ltemp;
	rightcnt--;
	return true;
}

void LList::prev(){
	if( fence != head){
		fence = fence->prev;
		leftcnt--;
		rightcnt++;
	}
}