这个问题我看下论坛也有很多的解答，可是我对比之后还是不明白我错哪里了~

求前辈们给指导啊~

先谢过了~

#include<stdio.h>
typedef struct stu
{
    int a;
    struct stu *next;
}STU;

void main()
{
    int n,i;
    STU *p,*head,*q;
    p=head=new STU;

    scanf("%d",&n);
    /*建立链表*/
    for(i=0;i<n;i++)
    {
        scanf("%d",&p->a);

        p->next=new STU;
        p=p->next;
   
    }
    /* 输出链表 */
    for (p = head; p != NULL; p = p->next)
        printf("%d", p->a);
    printf("\n");

    /* 逆置链表 */
    p = head;
    head = q = NULL;
    while (p != NULL)
    {
        if (head == NULL)
        {
            head = p;
            p = p->next;
            head->next = NULL;
        }
        else
        {
            q = p->next;
            p->next = head;
            head = p;
            p = q;
        }
    }
   
    /* 输出链表 */
    for (p = head; p != NULL; p = p->next)
        printf("%d", p->a);
    printf("\n");


        
        
   
   
   

   
}

p=head=new STU;
这个new是怎么回事？

void main()
{
    int n,i;
    STU *p,*head,*q;
    scanf("%d",&n);
    if (n <=0) {
        return;
    }     

    /*建立链表*/
    for(i=0;i<n;i++)
    {  
        if (i == 0) { // 第一次时候，是初始化链表头
            p=head=new STU;
        }
        else {         // 之后就可以直接在链表的末端来加入节点了
            p->next = new STU;
            p = p->next;
        }
        p->next = NULL;// 这个不可以少，否则会出错（访问非法内存），

        scanf("%d",&p->a);
    }

    /* 输出链表 */
    p = head;
    while (p != NULL) { // 用这个结构清晰一点
        printf("%d ", p->a);
        p = p->next;
    }

    printf("\n");


    /* 逆置链表 */
    p = head->next;
    head->next  = NULL;
   
    while (p != NULL) {
        q = p->next; // 保存下一个节点
        p->next = head;
        head = p;

        p = q;
    }     

    /* 输出链表 */
    p = head;
    while (p != NULL) { // 用这个结构清晰一点
        printf("%d ", p->a);
        p = p->next;
    }   

    printf("\n");                 
}

最好命名不要用 p q 什么的，用个有意义的名字

开辟新空间给head然后p指向head吧- -

恩，先谢过了~

编译通过~成功！
解释好详细~谢谢啦~

以后我会多注意变量的意思的

#include<stdio.h>
#include<malloc.h>
struct Node
{
        int value;
        struct Node * next;
};

typedef Node * LinkList;

void insert( LinkList *list, int value)
{
        if(  list == NULL)
        {
                Node * node= (Node*) malloc(sizeof(Node));
                node->value=value;
                node->next = NULL;
                *list =  node;
        }
        else
        {
                Node * head  = (Node *)malloc ( sizeof(Node));
                head->value = value;
                head->next=*list;
                *list = head;
        }
}       

void walk(LinkList list)
{
        Node * p = list;
        while( p )
        {
                printf("%d " , p->value);
                p = p->next;
        }
        printf("\n");
}

 
LinkList reverse( LinkList * list)
{
        LinkList tail;
        if ( NULL == list || NULL == (*list)->next)
                return *list;

        tail = reverse( & ((*list)->next));
        (*list)->next->next = *list;
        (*list)->next = NULL;
        return tail;
}

void destroy(LinkList *list)
{
        if ( *list == NULL)
                return;
        else
        {
                while((*list))
                {
                        free(*list);
                        *list = (*list)->next;
                }
                list = NULL;
        }
}

int main()
{
        int i;
        LinkList list = NULL;
        for ( i = 0 ; i < 3; i ++ )
        {
                insert(&list,i);
        }
        walk(list);
        list = reverse(&list);
        walk(list);
        destroy(&list);
}

1.
void insert( LinkList *list, int value)
{
        if(  list == NULL) // 按你的代码，这个分支永远没有办法执行
        {
                Node * node= (Node*) malloc(sizeof(Node));
                node->value=value;
                node->next = NULL;
                *list =  node;
        }
        else
        {
                Node * head  = (Node *)malloc ( sizeof(Node));
                head->value = value;
                head->next=*list;
                *list = head;
        }
}

if (list == NULL) 应该改成 if(*list == NULL)吧

2.
void destroy(LinkList *list)
{
    if ( *list == NULL)
        return;
    else
    {
        while((*list))
        {
            free(*list);  // 这个时候已经free list，下一句还 *list = (*list)->next;？？访问(*list)->next 会出错的
            *list = (*list)->next;
        }
        list = NULL; // 按你的逻辑 这个也应该是 *list = NULL。而不是list = NULL
    }
}

应该改成
void destroy(LinkList *list)
{
    if (list == NULL) {
        return;
    }

    Node *pDelete = *list;
    *list = NULL;

    while(pDelete != NULL) {
        Node *pNext = pDelete->next;
        free(pDelete);
        pDelete = pNext;
    }
}

恩，确实是有问题的。

析构改成了递归。

#include<stdio.h>
#include<malloc.h>
struct Node
{
        int value;
        struct Node * next;
};

typedef Node * LinkList;

void insert( LinkList *list, int value)
{
        if(  *list == NULL)
        {
                Node * node= (Node*) malloc(sizeof(Node));
                node->value=value;
                node->next = NULL;
                *list =  node;
        }
        else
        {
                Node * head  = (Node *)malloc ( sizeof(Node));
                head->value = value;
                head->next=*list;
                *list = head;
        }
}

void walk(LinkList list)
{
        Node * p = list;
        while( p )
        {
                printf("%d " , p->value);
                p = p->next;
        }
        printf("\n");
}

LinkList reverse( LinkList * list)
{
        LinkList tail;
        if ( NULL == list || NULL == (*list)->next)
                return *list;

        tail = reverse( & ((*list)->next));
        (*list)->next->next = *list;
        (*list)->next = NULL;
        return tail;
}

void destroy(LinkList *list)
{
        if ( *list == NULL )
                return;
        else
        {
                destroy(&(*list)->next);
        }
        free((*list));
        *list = NULL;
}

int main()
{
        int i;
        LinkList list = NULL;
        for ( i = 0 ; i < 3; i ++ )
        {
                insert(&list,i);
        }
        walk(list);
        list = reverse(&list);
        walk(list);
        destroy(&list);
}