C++程序设计实践指导1.4正整数转换为字符串改写要求实现

改写要求1：改为适合处理超长整数

#include <cstdlib>

#include <iostream>

#include <string>

using namespace std;



struct LinkNode

{

       short int data;

       LinkNode *next;

};

class STR

{

      string str;

      public:

             STR(string x)

             {

                     str=x;

             }

             struct LinkNode* itoa();

             struct LinkNode* reverse(LinkNode* pHead);

             void print(LinkNode* pHead)

             {

                  LinkNode* p=pHead;

                  p=p->next;

                  cout<<"n= ";

                  while(p)

                  {    

                      cout<<p->data;

                      p=p->next;

                  }

                  cout<<endl;

             }

};



struct LinkNode* STR::itoa()

{

     LinkNode* pHead=new LinkNode;

     pHead->next=NULL;

     LinkNode* p;

     p=pHead;

     int i=0;

     string s;

     int x=atoi(str.substr(i,1).c_str());

     while(1)

     {

             LinkNode* NewLinkNode=new LinkNode;

             NewLinkNode->next=NULL;

             NewLinkNode->data=x;

             p->next=NewLinkNode;

             p=NewLinkNode;

             s=str.substr(++i,1).c_str();

             if(s.length()==0)

             return pHead;

             x=atoi(s.c_str());

     }

     return pHead;

    

}



struct LinkNode* STR::reverse(LinkNode* pHead)

{

       LinkNode *p,*q;

       LinkNode *t;

       p=pHead->next;

       q=pHead->next->next;

       while(q)

       {

            t = q->next;  

            q->next = p;  

            p = q;  

            q = t;

       }

       pHead->next->next=NULL;

       pHead->next=p;

       return pHead;

}

              

int main(int argc, char *argv[])

{

    string n;

    LinkNode* pHead;

    cout<<"Input n: ";

    cin>>n;

    STR str(n);

    pHead=str.itoa();

   // pHead=str.reverse(pHead);

    str.print(pHead);

    system("PAUSE");

    return EXIT_SUCCESS;

}