一元多项式的表示及相加

#include <iostream>
#include<stdlib.h>

using namespace std;

typedef struct LNode
{
    int coef;//系数
    int expn;//指数
    struct LNode *next;
}LNode,*LinkList;


int CreateList_L(LinkList &L,int n)//默认指数按升序排列
{
    LinkList p,q;
    for(int i=0;i<n;i++)
    {
         p=(LinkList)malloc(sizeof(LNode));
         cout<<"输入元素系数：";
         cin>>p->coef;
         cout<<"输入元素指数：";
         cin>>p->expn;
         if(i==0)L=p;
         else q->next=p;
         q=p;
         p->next=NULL;
    }
   return 0;
}


int Display_L(LinkList L)
{
    if(!L)cout<<"f(x)=0"<<endl;
    else
    {
        cout<<"f(x)="<<L->coef;
        if(L->expn)cout<<"*"<<"x^"<<L->expn;
        L=L->next;
        while(L)
        {
            if(L->coef>0)
            {
                cout<<"+";
                cout<<L->coef<<"*"<<"x^"<<L->expn;
            }
            else cout<<L->coef<<"*"<<"x^"<<L->expn;
            L=L->next;
        }
    }
    return 0;
}


int AddPolyn(LinkList La,LinkList Lb,LinkList &Lc)
{
    LinkList pa,pb,p;
    int k=1;
    pa=La;pb=Lb;
    //确定“和多项式”的头结点
    while(k)
    {
         if(pa->expn<pb->expn){p=Lc=pa;pa=pa->next;k=0;}
         else if(pa->expn>pb->expn){p=Lc=pb;pb=pb->next;k=0;}
         else
         {
             pa->coef+=pb->coef;
             if(pa->coef)
             {
                  p=Lc=pa;
                  pa=pa->next;
                  k=0;
             }
             else
             {
                 pa=pa->next;
                 pb=pb->next;
                 if(!pa||!pb) break;
             }
         }
    }
    if(!pb&&pa){p=Lc=pa;pa=pa->next;}
    if(!pa&&pb){p=Lc=pb;pb=pb->next;}
    if(!pa&&!pb) Lc=NULL;
    //确定接下来的节点
    while(pa&&pb)
    {
        if(pa->expn<pb->expn){p->next=pa;p=pa;pa=pa->next;}
        else if(pa->expn>pb->expn){p->next=pb;p=pb;pb=pb->next;}
        else
        {
            pa->coef+=pb->coef;
            if(pa->coef)
            {
                  p->next=pa;
                  p=pa;
                  pa=pa->next;
                  pb=pb->next;
            }
            else
            {
                  pa=pa->next;
                  pb=pb->next;
            }

        }
    }
    while(!pb&&pa)
    {
        p->next=pa;
        p=pa;
        pa=pa->next;
    }
    while(!pa&&pb)
    {
        p->next=pb;
        p=pb;
        pb=pb->next;
    }
    return 0;
}



int main()
{
    LinkList La,Lb,Lc;
    int m,n;
    cout<<"请输入La中的元素个数：";
    cin>>m;
    CreateList_L(La,m);
    cout<<"请输入Lb中的元素个数：";
    cin>>n;
    CreateList_L(Lb,n);
    AddPolyn(La,Lb,Lc);
    Display_L(Lc);
    return 0;
}