求一个C++中用链表解决长整型数据四则运算问题,输入是a b 和是c

#include <iostream>
using namespace std;

/*创建节点*/
struct Node
{
int data;
Node * next;//后续指针
Node * pre;//前驱指针
};
/*创建双向链表*/
struct DoubleList
{
Node * phead;//头节点
Node * pback;//尾节点
};

/*添加节点*/
void AddNode(DoubleList * plist, int data)
{
//创建新节点
Node * ptemp = new Node;
ptemp->data = data;
ptemp->next = NULL;
ptemp->pre = NULL;

if(plist->phead == NULL)//空链表
{
plist->phead = plist->pback = ptemp;
return;
}
plist->pback->next = ptemp;
ptemp->pre = plist->pback;
plist->pback = ptemp;
}

/*在中间插入数据*/
bool InsertNode(DoubleList * plist, int data, int pos)
{
if(plist == NULL || plist->phead == NULL)//当链表是空或者头指针为空的时候,跳出
return false;
Node * ptemp = plist->phead;
for(int i=1; i<pos&&ptemp->next!=NULL; ++i)