struct shares *sort(struct shares **h) /* 选择排序算法 */
{
   struct shares *p,*q,*r,*s;
   p=q=(struct shares *)malloc(LEN);
   p=*h;
      while(p->next)
      {
         r=p;
         q=p->next;
         for(;q->next;q=q->next)
         {
             if(q->next->num>q->num) r=q;
                 if(p!=r)
                 {
                  s=r;
                  r=p;
                  p=s;
                 }
         }
          p=p->next;
      }
      p->next=NULL;
   return(p);
}