free()和链表的使用出错

[techie]

小弟在C primer plus上面看到一个例子，可是在vs2010中运行它时却出错了。

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define TSIZE 45

struct film {
char title[TSIZE];
int rating;
struct film * next;
};

int main(void)
{
struct film * head = NULL;
struct film * prev, * current;
char input[TSIZE];

puts("Enter first movie title:");
while((gets(input)!=NULL)&&(input[0]!='\0'))
{
current = (struct film *)malloc(sizeof(struct film));
if(head == NULL)
head = current;
else
prev->next = current;
current->next = NULL;
strcpy(current->title,input);
puts("Enter your rating <1-10>:");
if((scanf("%d",¤t->rating))==0)
{
puts("Enter error!");
exit(1);
}
while(getchar()!='\n')
continue;
puts("Enter next movie title (empty line to stop):");
prev = current;
}

if(head == NULL)
puts("No data enter!");
else
puts("Here is the movie list:");
current = head;
while(current != NULL)
{
printf("Movie: %s Rating: %d\n",current->title,current->rating);
current = current->next;
}
current = head;
while(current != NULL)
{
free(current);
current = current->next; /* error pointer! */
}
printf("Goodbye!\n");
return 0;
}
这个错误要如何解决啊，

[techie]

发现个新的问题，如5楼所说：
current = head;
struct file *p = NULL;//这样做编译无法通过，p不能被定义在这里。
while(current != NULL)
{
p = current-> next;
free(current);
current = p;
}

我把p定义在主函数刚开始的地方程序又能编译了：
struct film * head = NULL;
struct film * prev, * current;
struct film *p = NULL; //定义在这里编译就没有错误了，这是为什么啊？
char input[TSIZE];

[nice_cxf]

[Quote=引用 6 楼 xy598646744 的回复:]

发现个新的问题，如5楼所说：
current = head;
struct file *p = NULL;//这样做编译无法通过，p不能被定义在这里。
while(current != NULL)
{
p = current-> next;
free(current);
current = p;
}

我把p定义在主函数刚开始的地方程序又能编译了：
str……
[/Quote]
扩展名改成.cpp应该就可以了,vs系列支持的c标准太老

[maozhihui52102]

VC6.0下，CPP文件，无压力

[techie]

问题解决了，谢谢大家

[W170532934]

什么错误？？？

[techie]

free(current);
current = current->next;/*错误指针！*/

[Furney]

这个地方有问题哈。

while(current != NULL)
{
free(current);
current = current->next; 
}

[Cniao_zhi]

已经free了current指针，杂找current-next?

[自信男孩]

current = head;
while(current != NULL)
{
free(current);
current = current->next; /* error pointer! */
}
这段程序是有问题的，你已经释放了current，是不可以在使用了，在使用会出现未定义的（可能会是段错误）。改一下：
current = head;
struct file *p = NULL;
while(current != NULL)
{
p = current-> next;
free(current);
current = p;
}