双向循环链表实现任长度加法运算

问题遇到的现象和发生背景

双向循环链表实现任意长度整数加法

问题相关代码，请勿粘贴截图

#define _CRT_SECURE_NO_WARNINGS 
#include<stdio.h>
#include<stdlib.h>
#include<cstdio>
#include<cstring>
#include<string.h>
#include<iostream>
#include<malloc.h>
#define LEN sizeof(struct Sqlist)
using namespace std;
int aaa[10000000];
int pp = 0;
typedef struct Sqlist
{
    int data,num;//data值存储长整数的符号，1为正，-1为负，0代表长整数为0;num值存储除头节点节点的个数
    struct Sqlist* pro,* next;
}Sqlist;

struct Sqlist* creat()//生成链表 
{
    struct Sqlist* head;
    head = (struct Sqlist*)malloc(LEN);
    if (head == NULL)
        printf("无法分配内存\n");
    else
    {
        head->data = 0;
        head->num = 0;
        head->pro = head;
        head->next = head;
    }
    return(head);
}

void print(struct Sqlist* head)
{
    struct Sqlist* p;
    p = head;
    if (head->next == head)
        printf("longint error!\n");
    else
    {
        if (head->data == -1)
            printf("-");
        p = head->next;
        printf("%d", p->data);
        p = p->next;
        while (p != head)
        {
            if (p->data >= 0 && p->data < 10)
                printf("000%d", p->data);
            if (p->data >= 10 && p->data < 100)
                printf("00%d", p->data);
            if (p->data >= 100 && p->data < 1000)
                printf("0%d", p->data);
            if (p->data >= 1000)
                printf("%d", p->data);
            p = p->next;
        }
        printf("\n");
    }
}

void insert(struct Sqlist* head, struct Sqlist* p)
{
    p->next = head->next;
    head->next->pro = p;
    head->next = p;
    p->pro = head;
    head->num = head->num + 1;
}

void del(struct Sqlist* head, struct Sqlist* p)
{
    head->next = p->next;
    p->next->pro = head;
    free(p);
    head->num = head->num - 1;
}

struct Sqlist* get(char s[])
{
    struct Sqlist* head, * q;
    int i, j, l = 0;
    head = creat();
    if (s[0] > '0')
        head->data = 1;
    if (s[0] == '0')
        head->data = 0;
    if (s[0] == '-')
    {
        l = 1;
        head->data = -1;
    }
    j = strlen(s) - 1;
    for (i = l; i <= j; i++)
        s[i] = s[i] - '0';
    while (j - l >= 3)
    {
        q = (struct Sqlist*)malloc(LEN);
        q->data = s[j] + s[j - 1] * 10 + s[j - 2] * 100 + s[j - 3] * 1000;
        insert(head, q);
        j = j - 4;
    }
    if (j >= l)
    {
        q = (struct Sqlist*)malloc(LEN);
        q->data = 0;
        while (l <= j)
        {
            q->data = q->data * 10 + s[l];
            l++;
        }
        insert(head, q);
    }
    return(head);
}

void add(struct Sqlist* a, struct Sqlist* b)
{
    struct Sqlist* m, * n, * p, * chead, * q;
    if (a->num == 0 || b->num == 0)
        printf("长整数错误\n");
    else
    {
        m = a->pro;
        n = b->pro;
        chead = creat();
        while (m != a && n != b)
        {
            p = (struct Sqlist*)malloc(LEN);
            p->data = a->data * m->data + b->data * n->data;
            insert(chead, p);
            m = m->pro;
            n = n->pro;
        }
        while (m != a || n != b)
        {
            if (m == a)
            {
                p = (struct Sqlist*)malloc(LEN);
                p->data = b->data * n->data;
                n = n->pro;
                insert(chead, p);
            }
            else if (n == b)
            {
                p = (struct Sqlist*)malloc(LEN);
                p->data = a->data * m->data;
                m = m->pro;
                insert(chead, p);
            }
        }
        p = chead->next;
        chead->data = 0;
        while (p != chead)
        {
            if (p->data > 0)
            {
                chead->data = 1;
                break;
            }
            if (p->data < 0)
            {
                chead->data = -1;
                break;
            }
            p = p->next;
        }
        p = chead->pro;
        while (p != chead)
        {
            if (p->next != chead)
                p->data = p->data * chead->data + p->next->num;
            if (p->next == chead)
                p->data = p->data * chead->data;
            p->num = 0;
            if (p->data >= 10000)
                p->num = 1;
            if (p->data < 0)
                p->num = -1;
            p->data = p->data - p->num * 10000;
            p = p->pro;
        }
        p = chead->next;
        while (p->data == 0 && p->num == 0 && p->next != chead)
        {
            q = p;
            p = p->next;
            del(chead, q);
        }
        if (p->num > 0)
        {
            q = (struct Sqlist*)malloc(LEN);
            q->data = p->num;
            insert(chead, q);
        }
    }
    if (chead->next->data == 0)
        chead->data = 0;
    print(chead);
}



int main()
{
    struct Sqlist* a, * b;
    char s1[100], s2[100];
    int flag;
    printf("请输入数据\n");
    gets(s1);
    gets(s2);
    a = get(s1);
    b = get(s2);
    cout<<"运行结果为："<<endl; 
    add(a,b);

}

我想要达到的结果

需要输出结果位每四位一个逗号

数据结构+大数加法