c语言：多项式相加的实现

#include<iostream>
#include<stdio.h>
#include<math.h>
#define NULL 0
#define LEN sizeof(struct ADD)
using namespace std;
struct ADD            //定义结构体
{
	float xishu;      //数据域
	int zhishu;
    struct ADD *next;  //指针域
}; 
void Initadd(ADD L)   //单链表初始化函数
{
	L.xishu = 0;
	L.zhishu = 0;
	L.next = NULL;
}
struct ADD *Creatadd(void)   //前插法创建单链表
{
	struct ADD *head,*p, *q;
	int n = 0;
	p = (struct ADD*)malloc(LEN);
	q = p;
	cin >> p->xishu >> p->zhishu;
	head= NULL;
	while (p->xishu!=0)
	{
		n++;
		if (n == 1) head = p;
		else q->next = p;
		q = p;
		p = (struct ADD*)malloc(LEN);
		cin >> p->xishu >> p->zhishu;
	}
	q->next = NULL;
	return head;
};
void ADDadd(struct ADD &p1,struct ADD &p2) //相加函数
{
   struct ADD *a,*b,*c,*d;
   a = &p1;    //指针a指向p1
   b = &p2;    //指针b指向p2
	c = a;      //指针c指向指针a
	while (a&&b)
	{
		if (a->zhishu < b->zhishu)       
		{
			c =