链表释放空间

[xidianxiancai]

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <assert.h>
#define elemtype int

typedef struct Node
{
elemtype data;
struct Node *next;
}Node;


int main(void)
{
Node *head, *p1, *p2, *p3;
p1 = p2 = (Node *)malloc(sizeof(Node *));
if (p1 == NULL)
{
printf("failure in memory.\n");
exit(0);
}
head = p1;
scanf("%d",&p1->data);
p1->next = NULL;
if (p1->data == 0)
{
printf("List is empty.\n");
return 0;
}
while (p2->data != 0)
{
if (!(p2 = (Node *)malloc(sizeof(Node *))))
{
printf("failure in memory.\n");
exit(0);
}
scanf("%d",&p2->data);
getchar();
p2->next = NULL;
p3 = p1;
p1->next = p2;
p1 = p1->next;
}
p3->next = NULL;
printf("List is made successfully.\n");
//以下是对该建立好的链表进行空间的释放,但是释放不成功,请问该如何改？如何进行释放呢？
p2 = head->next;
p1 = head;
free(p1);
head = NULL;
p1 = p2;
while (p1!=NULL)
{
p1 = p1->next;
free(p2);
p2 = p1;
}
return 0;
}

[ainijing]

void cleardata()
{
Node *tmp;
while( tableinfo!= NULL )
{
tmp=( Node )tableinfo->np;
free( tableinfo );
tableinfo = tmp;
}
}

[fengogo]

p1 = p2 = (Node *)malloc(sizeof(Node *)); -> p1 = (Node *)malloc(sizeof(Node));

do
{
if (!(p2 = (Node *)malloc(sizeof(Node))))
{
printf("failure in memory.\n");
exit(0);
}
scanf("%d",&p2->data);
getchar();
p2->next = NULL;
p1->next = p2;
p1 = p1->next;
} while (p2 -> data != 0);

p1 = head;
while(p1 != NULL)
{
p2 = p1 -> next;
free(p1);
p1 = p2;
}
head = NULL;

[breezes2008]

释放链表：
struct node *p,*start,*temp;
for(p=start;p!=NULL;p=temp)
{
temp=p->next;
free(p);
}

====================================================================
常见这样“释放”：for(p=start;p!=NULL;p=p->next) //错误，发生内存泄漏.

[KevinHo]

第一个问题，分配内存大小的计算是sizeof(Node)，不是sizeof(Node*)，因为你是给结构体变量指针分配指针！
另外你的编程逻辑真的不是太好……当然这只是给你提意见，总觉得你的思路不清晰

[liliangbao]

1.(Node *)malloc(sizeof(Node *)都要改为(Node *)malloc(sizeof(Node))
2.释放链表：
p1 = head;
while(p1 != NULL)
{
p2 = p1 -> next;
free(p1);
p1 = p2;
}
即可！
3.看一看如何建立链表的常用的两种方法：头插法和尾插法
比较与你的不同你会受益匪浅的呦！

[bfhtian]

分配内存就没有成功

[sjhui19840325]

up 2楼写的精练

#include <stdio.h> 
#include <stdlib.h> 
#include <malloc.h> 
#include <assert.h> 
#define elemtype int 

typedef struct Node 
{ 
	elemtype data; 
	struct Node *next; 
}Node; 


int main(void) 
{ 
	Node *head, *p1, *p2;   //一直没明白lz用p3做什么
    p1 = (Node *)malloc(sizeof(Node)); 
	if (p1 == NULL) 
	{ 
		printf("failure in memory.\n"); 
		exit(0); 
	} 	
	scanf("%d",&p1->data); 
	p1->next = NULL; 
	if (p1->data == 0) 
	{ 
		printf("List is empty.\n"); 
		free(p1);   // 你在退出前要释放空间
		return 0; 
	} 
	head = p1;
	while (p1->data != 0) 
	{ 
		if (!(p2 = (Node *)malloc(sizeof(Node)))) 
		{ 
			printf("failure in memory.\n"); 
			exit(0); 
		} 
        scanf("%d",&p2->data); 
		getchar(); 
		p2->next = NULL; 
		p1->next = p2; 
		p1 = p1->next; 
    } 
	printf("List is made successfully.\n"); 

	while (head!=NULL) 
	{ 
		p2 = head;
       	head = head->next; 
		free(p2); 		 
	} 

    return 0; 
} 

[ypb362148418]

你用malloc那就用free释放啊

[wuyanchao]

没成功 所以没释放