#include <stdio.h>
#include <stdlib.h>
#include <time.h>
typedef int mytype;
typedef struct Node
{
    mytype xi;
    mytype zhi;
    Node *next;
}PNode,*PList;
void initPList(PList &L,int n)
{
    L=(PList)malloc(sizeof(PNode));
    L->next=NULL;
    PList p=L;
    for(int i=0;i<n;i++)
    {
        PList s=(PList)malloc(sizeof(PNode));
        s->xi=rand()%23-30;
        s->zhi=i;
        p->next=s;
        s->next=NULL;
        p=s;
    }
}
void printPList(PList L)
{
    PList p=L->next;
    while(p)
    {
        printf("%dx%d",p->xi,p->zhi);
        p=p->next;
    }
    printf("\n");
}
void addPList(PList LA,PList LB)
{
    PList p=LA->next;
    PList q=LB->next;
    PList s=LB;
    while(p&&q)
    {
        if(p->zhi<q->zhi)
        {
            s->next=p;
            s=p;
            p=p->next;
        }
        if(p->zhi>q->zhi)
        {
            s->next=q;
            s=q;
            q=q->next;
        }
        if(p->zhi=q->zhi)
        {
            mytype sum;
            sum=p->xi+q->xi;
            if(sum!=0)
            {
                q->xi=sum;
                s=q;
                s->next=q;
                q=q->next;
                p=p->next;
            }
            else
            {
                q=q->next;
                p=p->next;
            }
        }
    }
    s->next=p?p:q;
}
int main()
{
    PList PLA,PLB;
    initPList(PLA,6);
    initPList(PLB,8);
    printPList(PLA);
    printPList(PLB);
    addPList(PLA,PLB);
    printPList(PLB);
}

改了那里  还是不能输出两个多项式 相加后的结果

还有没有大佬帮忙指出一下问题

谢谢，看了你的之后  明白了 问题所在