数据结构C语言版：一元稀疏多项式

#include<stdio.h> 声明部分：源代码含有2个文件
#include<malloc.h>
typedef struct pnode // 定义指针//
{int coef; //定义系数//
int exp; //定义指数//
struct pnode *next;
}pnode;

pnode * creat() //creat函数用来存放多项式//
{int m,n;
pnode *head,*rear,*s;
head=(pnode *)malloc(sizeof(pnode));
rear=head;
printf("\n输入指数(按递增顺序输入)：");
scanf("%d",&m);
printf("输入一元式系数(0为退出)：");
scanf("%d",&n);
do
{
s=(pnode *)malloc(sizeof(pnode));
s->coef=n; //n为系数//
s->exp=m; //m为指数//
rear->next=s;
s->next=NULL;
rear=s;
printf("\n输入指数(按递增顺序输入)：");
scanf("%d",&m);
printf("输入一元式系数(0为退出)：");
scanf("%d",&n);
}while(n);
return head;
}

pnode * add(pnode *heada,pnode *headb)
{pnode *headc,*a,*b,*s,*rearc;
int sum;
a=heada->ne