void Paixu(Node *h)
{
    int p, t,m;
    Node *q, *r,*head;
    head=h;
    do
    {
        p = h->n; q = h; r = h;
        do
        {
            if (r->n < p)
            { p = r->n; q = r; }
            r = r->next;
        } while (r != NULL);
        if (r != h)
        {
            t = h->n;
            m = h->a;
            h->n = q->n;
            h->a = q->a;
            q->n = t;
            q->a = m;
        }
        h = h->next;
    } while (h != NULL);
    h=head;
    }

请楼主贴出完整代码。
这是一个有头节点的链表。楼主需百度一下链表的知识。

这个还少了链表的结构体。