代码末尾对malloc（）分配的内存内存进行释放，但加上这段代码后编译会出错，不释放反而可以。不说说凡是有malloc（）都要free（）吗？
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define TSIZE 45
struct film
{
char title[TSIZE];
int rating;
struct film *next; /*指向链表的下一个结构*/
};
int main(void)
{
struct film * head = NULL;
struct film * current, * prev;
char input[TSIZE];
/*收集并存储信息*/
puts("enter the first movie title:");
while (gets(input) != NULL && input[0] != "\0")
{
current = (struct film *)malloc(sizeof(struct film));
if (head == NULL) /*第一个结构*/
{
head = current;
}
else /*后续结构*/
{
prev->next = current;
}
current->next = NULL;
strcpy(current->title, input);
puts("enter the movie rating(0-10)");
scanf("%d", ¤t->rating);
while (getchar() != "\n")
{
continue;
}
puts("enter the next movie title(enter empty line to quit):");
prev = current;
}
/*给出电影列表*/
if (head == NULL)
{
puts("no date entered!");
}
else
{
printf("here is the movie list:");
}
current = head;
while (current != NULL)
{
printf("Movie: %s rating: %d", current->title, current->rating);
current = current->next;
}
/*释放分配的内存*/
current = head;
while (current != NULL)
{
free(current);
current = current->next;
}
printf("Bye!");
return 0;
}
解决方案
20
free(current);
current = current->next; // 前面一行已经释放了current，那么这里就不能再使用current->next了
应该是这样：
tmp = current->next;
free(current);
current = tmp;
current = current->next; // 前面一行已经释放了current，那么这里就不能再使用current->next了
应该是这样：
tmp = current->next;
free(current);
current = tmp;
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