//7定义一个排序函数
struct student *sort(struct student *h)
{
    int i,j,k;
    struct student *p1,*p2,*p3;
    printf("请选择排序方式1按学号排序2按总分排序\n");
    scanf("%d",&j);getchar();
    if(j==1)
   {  p1=h;
         p2=p1->next;
     
     
     
     for(i=0;i<n-1;i++)
     {
         for(k=0;k<n-i-1;k++)
         {
             if(p1->num>p2->num)
             {p3=p1;
              p1=p2;
              p2=p3;
             }
           p1=p1->next;
           p2=p1->next;
         }
     }
     
}
  head=p1;
  return(head); }