C++ 链表操作（建立，删除，添加）

// linklist.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "malloc.h"
#include "stdlib.h"
#define NULL 0
#define LEN sizeof(struct student)
struct student
{
 long num;
 float score;
 struct student* next;
};
int n;
struct student* creat()
{
    struct student *head;
 struct student *p1,*p2;
 n=0;
 p1=p2=(struct student*)malloc(LEN);
 scanf("%ld",&p1->num);
 scanf("%f",&p1->score);
 head=NULL;
 while (p1->num!=0)
 {
  n++;
  if (n==1)
  {
   head=p1;
  }
  else
  {
   p2->next=p1;
  }
  p2=p1;
  p1=(struct student*)malloc(LEN);
  scanf("%ld",&p1->num);
  if (p1->num==0)
   break;
  scanf("%f",&p1->score);
 }
 p2->next=NULL;
    return (head);
};
void print(struct student *head)
{
 struct student *p;
 printf("\n New,These %d records are:\n",n);
 p=head;
 if (head!=NULL)
 {
  do
  {
   printf("%d    %5.1f\n",p->num,p->score);
   p=p->next;
  }while (p!=NULL);
 }
}
struct student* insert(struct student *head,struct student *stud)
{
 struct student *p0, *p1, *p2;
 p1=head;
    p0=stud;
 if (head==NULL)
 {
  head=p0;
  p0->next=NULL;//insert into head point
 }
 else
 {
  while ((p0->num>p1->num)&&(p1->next!=NULL))
  {
   p2=p1;      //p2 is point to just p1 point to node;
   p1=p1->next;
  }
  if (p0->num<=p1->num)
  {
            if (p1==head)
   {
    head=p0;//insert into before first node
   }
   else
   {
                p2->next=p0;//insert into after point p2
   }
   p0->next=p1;
  }
  else
  {
            p1->next=p0;  //insert into after last point
   p0->next=NULL;
  }
 }
 n++;
    return(head);
};
struct student* del(struct student *head,long num)
{
 struct student *p1, *p2;
 if (head==NULL)
 {
  printf("\n list Null!\n");
  return (head);
 }
 p1=head;
 while (num!=p1->num&&p1->next!=NULL)
 //find num if equal p1->num
 {
  p2=p1;
  p1=p1->next;
 }
 if (num==p1->num)
 {
  if (p1==head)
   head=p1->next;//delete head node because num=head.num
  else
   p2->next=p1->next;//delete node. node is not head point
  printf("delete:%ld\n",num);
  n--;
 }
 else
 {
  printf("%ld not been found!\n",num);
 }
 return (head);
};
int _tmain(int argc, _TCHAR* argv[])
{
 struct student *head,*end;
 head=creat();
    print(head);
    struct student insertnode;
 insertnode.num=3;
 insertnode.score=900;
 head=insert(head,&insertnode);
 print(head);
 head=del(head,3);
 print(head);
 return 0;
}