小弟我这个链表有点有关问题，找了半天没找着

#include"stdio.h"
#include"malloc.h"
#include"string.h" 
#define NULL 0
struct stu{
      char *name;
      char sex;
      int age;
      int num;
          };
struct stu *creat(int n)
{
    struct stu *head,*pf,*pd;
    for(int i=0;i<n;i++)
    {
        pd=(struct stu*)malloc(sizeof(struct stu));
        printf("input Number and Age\n");
        scanf("%d%d",&pb->num,&pb->age);
       if(i==0)
        head=pf=pd;
        else {
             pf->next=pb;
             pb->next=NULL;    
             pf=pb;
             }
    }
    return head;
}
struct stu *search(struct stu *head,int num)
    {
    struct stu *pf,*pb;
    pb=head;
    while(pb->num!=num&&pb->next!=NULL)
       {
        pb=pb->next; 
        }
       if(pb->num=num) ruturn pb;
       if(pb->num!=num&&pb->next==NULL)
       printf("没有该同学");
       
       
    }
struct stu *delete(struct stu *head,int num)
{
    struct stu *pf,*pb;
    if(head==NULL)
    {
      printf("这表是个空链表");
      goto end;
    }
    pb=head;
    while(pb->num!=num&&pb->next!=NULL)
    {
        pf=pb;pb=pb->next;
    }
    if(pb->num=num)
      {
        if(pb==head)
        head=pb->next;
        else pf->next=pb->next;
       printf("节点已经删除");
       free(pb);
      }
      else printf("没有这个节点");
       end;
     } 
 struct stu *insert(struct stu *head,*pi)
 {
     struct stu *pf,*pb;
     if(head==NULL)
     {
         head=pi;
         pi-next=NULL;
     }
     else
     {
         pb=head;
        while(pi->num>pb->num&&pb->next!=NULL)
        {
            pf=pb;
            pb=pf-next;
        }
         if(pi->num<=pb->num) 
        {
           if(head==pb)
             {
             head=pi;
            }
         else
            {
               pf->next=pi;
            pi-next=pb;
            }
         else {
             pb->next=pi;
             pi->next=NULL;
             }
        }
    }
    return head;
 }
 int main()
 {
     struct *head,*pi;
     int num;
     printf("请输入创建几个同学成绩单");
     scanf("%d",&num);
     head=creat(num);
     print(head);
     printf("请输入查找同学的学号");
     scanf("%d",&num);
     print(search(head,num));
     printf("请输入要被删除同学的学号");
     scanf("%d",&num);
     print(delete(head,num));
    printf("请输入要插入同学的学生号和年龄: "); 
    pi=(struct stu *)malloc(sizeof(struct stu));
    scanf("%d%d",&pi->num,&pi->age);
    print(insert(head,pi));
 }