关于异常：读取访问权限冲突，p是oxCEDECEE7的疑问

在调试过程中第71行会出现异常，读取访问权限冲突，p是oxCEDECEE7

typedef struct Node1 {
    int data[MaxCol];
    struct Node1* next;
};
typedef struct Node2 {
    int row, col;
    Node1* next;
};

void LinkTable(Node2*h1,Node2*h2,Node2*&h){
    int i, j, k;
    Node1* p = h1->next, * q, * s, * r;
    r = (Node1*)malloc(sizeof(Node1));
    cout << "连接字段是，第一个表序号，第二个表序号：";
    cin >> i >> j;
    h = (Node2*)malloc(sizeof(Node2));
    h->row = 0;
    h->col = h1->col + h2->col;
    while (p != NULL) {
        q =h2->next;
        while (q != NULL) {
            if(p->data[i-1]==q->data[j-1])
            {
                s = (Node1*)malloc(sizeof(Node1));
                for (k = 0; k < h1->col; k++)
                    s->data[k] = p->data[k];
                for (k = 0; k < h2->col; k++)
                    s->data[h1->col + k] = q->data[k];
                if (h->next == NULL)
                    h->next = s;
                else
                    r->next = s;
                r = s;
                h->row++;
            }
            q = q->next;
        }
        p = p->next;
    }
    r->next = NULL;
}

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