求解,指针链表问题
我看书上的一个例子,自己打上去就是运行不了,提示指针出了问题,大虾帮忙看看这是怎么了file1:
#include<stdio.h>
#include<malloc.h>
#define NULL 0
#define LEN sizeof(struct student)
struct student
{
long num;
float score;
struct student *next;
};
file2
#include"define.h"
extern int n;
struct student *creat(void)
{
struct student *head;
struct student *p1,*p2;
n=0;
p1=p2=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
head=NULL;
while (p1->num!=0)
{
n=n+1;
if(n==1)
head=p1;
p2=p1;
p1=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
}
p2->next=NULL;
return(head);
free(p1);
free(p2);
}
file3
#include"define.h"
extern int n;
void print(struct student *head)
{
struct student *p=NULL;
printf("\nNow,These %d records are:\n",n);
p=head;
if(head!=NULL)
while(p!=NULL)
{
printf("%-10ld%5.1f\n",p->num,p->score);
p=p->next;
}
free(p);
}
file4
#include"define.h"
int n;
extern struct student *creat(void);
extern void print(struct student *head);
void main()
{
print(creat());
}