如何在C++中用链表实现多项式的加减乘法

刚好做过
#include<iostream>
using namespace std;
#include<stdlib.h>
typedef int ElemType;

struct Pnomial //Pnomial=Polynomial(多项式)
{
ElemType co,de1,de2,de3;
//co=coefficient(系数), de=degree(次数)

Pnomial* next;
};

Pnomial *ADD(Pnomial *ph);

void mul(Pnomial *ph,Pnomial *qh);

void main()
{
Pnomial *ph,*qh,*p,*s,*q;
//ph表头指针,p移动指针,q临时储存结点

ph=p=new Pnomial;
qh=q=new Pnomial;

cout<<"\nthe 1st Polynomial:"<<endl;
cout<<"give coefficient value:"<<endl;

while(p->co!=0)
{
s=new Pnomial;

cin>>s->co;
if(s->co!=0)
{
cout<<"x^";
cin>>s->de1;
cout<<"y^";
cin>>s->de2;
cout<<"z^";
cin>>s->de3;
cout<<&quo