双向链表问题，debug 在while((tmp->pnext) !=NULL) stm32会重启 - 编程论坛

#2

我善治鬼2021-08-19 11:19

链表结构其实是现实中自行车链条的仿真, 只有文字没有图形是很难描述清楚的,
你应该使用画图软件将链表每一步动作都画出来, 才能确定哪里出了问题

#3

自由而无用2021-08-19 11:41

//https://www.bccn.net/run/

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

typedef unsigned char uint8_t;
typedef unsigned int  DRAW_PARA;

typedef struct {
    uint8_t title_num;
    DRAW_PARA *title;
    uint8_t content_num;
    DRAW_PARA *content;
}PAGE_DATA;

typedef struct page_config
{
    uint8_t page_n;
    PAGE_DATA *temp;
    char (*pdata)[40];
    struct page_config *pnext;
    struct page_config *pprev;
}PAGE_CONFIG;

PAGE_DATA page_data[10];

PAGE_CONFIG* initLine(PAGE_CONFIG *head)
{

    head = (PAGE_CONFIG*)malloc(sizeof(PAGE_CONFIG));

    head->pprev=NULL;
    head->pnext=NULL;

    PAGE_CONFIG *list=head;
//follow
    printf("head = %p next = %p\n", head, head->pnext);
    for (int i=0; i<5; i++) {
        PAGE_CONFIG *body=(PAGE_CONFIG*)malloc(sizeof(PAGE_CONFIG));
        body->pprev=NULL;
        body->pnext=NULL;
        body->temp = &page_data[i];
        body->page_n = i;
        body->pdata = NULL;
//follow
        printf("body = %p ", body);
        list->pnext = body;
        printf("pnext = %p ", list->pnext);

        body->pprev = list;
//follow
        list=list->pnext;
        printf("list = %p\n", list);
    }
//follow
    printf("head = %p\n", head);
    return head;
}

PAGE_CONFIG* InsertTailNode(PAGE_CONFIG *head)
{
    int nnn = 0;
    PAGE_CONFIG *tmp = head;
    if(head == NULL)return 0;

    puts("enter InsertTailNode");
    printf("%p, %p\n", tmp, tmp->pnext);
//segment fault
    //tmp = tmp->pnext;

    while((tmp->pnext) != NULL) {
        tmp = tmp->pnext;
        nnn++;
    }

    printf("nnn = %d\n", nnn);

    PAGE_CONFIG *tailnode = (PAGE_CONFIG*)malloc(sizeof(PAGE_CONFIG));
    if(tailnode == NULL)return 0;

    tailnode->pdata = NULL;
    tailnode->temp = NULL;
    tailnode->page_n = nnn + 1;
    tmp->pnext = tailnode;
    tailnode->pprev = tmp;
    tailnode->pnext = NULL;

    puts("exit InsertTailNode");
    return head;
}

int main(int argc, char *argv[])
{
    PAGE_CONFIG head, *nhead;
    nhead = initLine(&head);
//follow
    printf("%p, %p\n", &head, nhead);

    //InsertTailNode(&head);
//follow
    InsertTailNode(nhead);
    puts("end of main!");

    return 0;
}

[此贴子已经被作者于2021-8-19 12:32编辑过]

#4

自由而无用2021-08-19 12:33

print result:

head = 0x15ec010 next = (nil)
body = 0x15ed050 pnext = 0x15ed050 list = 0x15ed050
body = 0x15ed080 pnext = 0x15ed080 list = 0x15ed080
body = 0x15ed0b0 pnext = 0x15ed0b0 list = 0x15ed0b0
body = 0x15ed0e0 pnext = 0x15ed0e0 list = 0x15ed0e0
body = 0x15ed110 pnext = 0x15ed110 list = 0x15ed110
head = 0x15ec010
0x7ffcbfd88020, 0x15ec010
enter InsertTailNode
0x15ec010, 0x15ed050
nnn = 5
exit InsertTailNode
end of main!

#5

rjsp2021-08-19 14:56

PAGE_CONFIG* initLine(PAGE_CONFIG * head){

head=(PAGE_CONFIG*)malloc(sizeof(PAGE_CONFIG));

这一句就不对了吧，你修改 head 这个临时变量干什么？

#6

j155062718412021-08-19 15:07

谢谢各位，代码我在网上抄的，是比较奇怪

#7

rjsp2021-08-19 15:17

程序代码：

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

typedef struct page_config
{
    int value;

    struct page_config* next;
    struct page_config* prev;

} PAGE_CONFIG;

void list_pushback( PAGE_CONFIG** phead, int value )
{
    PAGE_CONFIG* prev = NULL;
    PAGE_CONFIG** ptail = phead;
    for( ; *ptail; prev=*ptail, ptail=&prev->next );

    (*ptail) = malloc( sizeof(PAGE_CONFIG) );
    (*ptail)->value = value;
    (*ptail)->prev = prev;
    (*ptail)->next = NULL;
}

void list_print( PAGE_CONFIG* phead )
{
    for( ; phead; phead=phead->next )
        printf( "%d%c", phead->value, " \n"[phead->next==NULL] );
}

int main( void )
{
    PAGE_CONFIG* head = NULL;
    list_print( head );

    list_pushback( &head, 0 );
    list_print( head );

    list_pushback( &head, 1 );
    list_print( head );

    list_pushback( &head, 2 );
    list_print( head );
}