C 从函数返回链表时出现分段错误
我有下面的代码,它打印文件夹中有结尾的文件。 默认情况下,它还会显示以“SCL_10m.tif”结尾的文件。 这是迄今为止行之有效的版本:C 从函数返回链表时出现分段错误,c,linked-list,segmentation-fault,C,Linked List,Segmentation Fault,我有下面的代码,它打印文件夹中有结尾的文件。 默认情况下,它还会显示以“SCL_10m.tif”结尾的文件。 这是迄今为止行之有效的版本: #include <dirent.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include "gdal/gdal.h" #include "gdal/cpl_conv.h" #include <stdio.h> #i
#include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "gdal/gdal.h"
#include "gdal/cpl_conv.h"
#include <stdio.h>
#include <time.h>
// Linked-List
typedef struct nlist{
char *data;
struct nlist *next;
}Node;
// Function to replace a string with another
// string
char* str_replace(char* string, const char* substr, const char* replacement) {
char* tok = NULL;
char* newstr = NULL;
char* oldstr = NULL;
int oldstr_len = 0;
int substr_len = 0;
int replacement_len = 0;
newstr = strdup(string);
substr_len = strlen(substr);
replacement_len = strlen(replacement);
if (substr == NULL || replacement == NULL) {
return newstr;
}
while ((tok = strstr(newstr, substr))) {
oldstr = newstr;
oldstr_len = strlen(oldstr);
newstr = (char*)malloc(sizeof(char) * (oldstr_len - substr_len + replacement_len + 1));
if (newstr == NULL) {
free(oldstr);
return NULL;
}
memcpy(newstr, oldstr, tok - oldstr);
memcpy(newstr + (tok - oldstr), replacement, replacement_len);
memcpy(newstr + (tok - oldstr) + replacement_len, tok + substr_len, oldstr_len - substr_len - (tok - oldstr));
memset(newstr + oldstr_len - substr_len + replacement_len, 0, 1);
free(oldstr);
}
free(string);
return newstr;
}
Node* insert(Node*, char*);
void show(Node*);
//Function to insert an element in the linked-list
Node* insert(Node *Head, char *value)
{
Node *new_string;
new_string = (Node *)malloc(sizeof(Node));
new_string->data = malloc(strlen(value)+1);
strcpy(new_string->data,value);
Node *check;
check = (Node *)malloc(sizeof(Node));
if(Head == NULL){
Head = new_string;
Head->next = NULL;
}
else{
check = Head;
while(check->next != NULL)
check = check->next;
check->next = new_string;
new_string->next = NULL;
}
return Head;
}
//Function to show the elements in the linked-list
void show(Node *Head)
{
Node *check;
check = (Node *)malloc(sizeof(Node));
check = Head;
if (check == NULL){
return;
}
while(check != NULL) {
printf("%s", check->data);
check=check->next;
}
printf("\n");
}
//Function to find the files in the folder recursively based on
// a wildcard, and adding them to a linked-list
void listFilesRecursively(char *path, char *suffix);
//checks if a string ends with a substring
int string_ends_with(const char * str, const char * suffix)
{
int str_len = strlen(str);
int suffix_len = strlen(suffix);
return
(str_len >= suffix_len) &&
(0 == strcmp(str + (str_len-suffix_len), suffix));
}
void listFilesRecursively(char *basePath, char *suffix)
{
char path[1000];
struct dirent *dp;
DIR *dir = opendir(basePath);
Node *Head = NULL;
if (!dir)
return;
while ((dp = readdir(dir)) != NULL)
{
if (strcmp(dp->d_name, ".") != 0 && strcmp(dp->d_name, "..") != 0)
{
strcpy(path, basePath);
strcat(path, "/");
strcat(path, dp->d_name);
if (string_ends_with(path, suffix))
Head = insert(Head, path);
listFilesRecursively(path, suffix);
}
}
show(Head);
closedir(dir);
}
int main()
{
char path[100];
char suffix[100];
// Input path from user
// Suffix Band Sentinel-2 of Type B02_10m.tif
printf("Enter path to list files: ");
scanf("%s", path);
printf("Enter the wildcard: ");
scanf("%s", suffix);
char *SCL_suffix = "SCL_10m.tif";
listFilesRecursively(path, suffix);
listFilesRecursively(path, SCL_suffix);
return 0;
}
#包括
#包括
#包括
#包括
#包括“gdal/gdal.h”
#包括“gdal/cpl_conv.h”
#包括
#包括
//链表
类型定义结构列表{
字符*数据;
结构nlist*next;
}节点;
//函数将字符串替换为另一个字符串
//串
char*str_替换(char*string,const char*substr,const char*replacement){
char*tok=NULL;
char*newstr=NULL;
char*oldstr=NULL;
int oldstr_len=0;
int substr_len=0;
整数替换_len=0;
newstr=strdup(字符串);
substr_len=strlen(substr);
更换=斯特伦(更换);
if(substr==NULL | | replacement==NULL){
返回新闻TR;
}
而((tok=strstrstr(newstr,substr))){
oldstr=newstr;
oldstr_len=strlen(oldstr);
newstr=(char*)malloc(sizeof(char)*(oldstr_len-substr_len+replacement_len+1));
if(newstr==NULL){
免费(oldstr);
返回NULL;
}
memcpy(newstr、oldstr、tok-oldstr);
memcpy(newstr+(tok-oldstr),替换,替换;
memcpy(newstr+(tok-oldstr)+替换项,tok+子项,oldstr-子项-(tok-oldstr));
memset(newstr+oldstr-substr-len+replacement-len,0,1);
免费(oldstr);
}
自由(弦);
返回新闻TR;
}
节点*插入(节点*,字符*);
虚空显示(节点*);
//函数在链表中插入元素
节点*插入(节点*头,字符*值)
{
节点*新的_字符串;
new_string=(Node*)malloc(sizeof(Node));
新建字符串->数据=malloc(strlen(值)+1);
strcpy(新字符串->数据、值);
节点*检查;
检查=(节点*)malloc(sizeof(节点));
if(Head==NULL){
头=新的_字符串;
Head->next=NULL;
}
否则{
检查=头部;
while(检查->下一步!=NULL)
检查=检查->下一步;
检查->下一步=新字符串;
新建字符串->下一步=空;
}
回流头;
}
//函数以显示链接列表中的元素
无效显示(节点*头部)
{
节点*检查;
检查=(节点*)malloc(sizeof(节点));
检查=头部;
如果(检查==NULL){
返回;
}
while(检查!=NULL){
printf(“%s”,检查->数据);
检查=检查->下一步;
}
printf(“\n”);
}
//函数以基于递归方式查找文件夹中的文件
//一个通配符,并将其添加到链接列表中
递归地作废列表文件(char*路径,char*后缀);
//检查字符串是否以子字符串结尾
int字符串以(常量字符*字符串,常量字符*后缀)结尾
{
int str_len=strlen(str);
int后缀_len=strlen(后缀);
返回
(str_len>=后缀_len)&&
(0==strcmp(str+(str_len-后缀_len),后缀));
}
递归作废列表文件(字符*基本路径,字符*后缀)
{
字符路径[1000];
结构方向*dp;
DIR*DIR=opendir(基本路径);
Node*Head=NULL;
如果(!dir)
返回;
而((dp=readdir(dir))!=NULL)
{
如果(strcmp(dp->d_name,“.”)=0和&strcmp(dp->d_name,“…”)!=0)
{
strcpy(路径、基本路径);
strcat(路径“/”;
strcat(路径,dp->d_名称);
if(字符串以(路径,后缀)结尾)
头部=插入(头部,路径);
递归地列出文件(路径、后缀);
}
}
秀(头);;
closedir(dir);
}
int main()
{
字符路径[100];
字符后缀[100];
//来自用户的输入路径
//B02_10m.tif型后缀带Sentinel-2
printf(“输入列表文件的路径:”);
scanf(“%s”,路径);
printf(“输入通配符:”);
scanf(“%s”,后缀);
char*SCL_suffix=“SCL_10m.tif”;
递归地列出文件(路径、后缀);
递归地列出文件(路径、SCL_后缀);
返回0;
}
我开始编写这段代码,做了一些修改,最重要的是,我没有通过调用show(Head)递归地打印函数listfiles中生成的链表,而是希望将列表返回到主函数以进行其他处理(同时迭代两个列表,这是未来的工作)
但是,在main()中执行此操作并递归调用函数listfiles两次后,我遇到了一个分段错误
根据某些来源,如果函数传递或返回指向堆栈上某个对象的指针,则会发生分段错误,堆栈是存储临时变量的内存区域。我一直在递归地检查listfiles函数,在其中处理指针,但我无法解决这个问题。如果您能在这个问题上提供一些帮助,我们将不胜感激
下面是导致分段错误的代码的修改版本
include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "gdal/gdal.h"
#include "gdal/cpl_conv.h"
#include <stdio.h>
#include <time.h>
// Node Structure of Linked-List
typedef struct nlist{
char *data;
struct nlist *next;
}Node;
// Function to replace a string with another
// string
char* str_replace(char* string, const char* substr, const char* replacement) {
char* tok = NULL;
char* newstr = NULL;
char* oldstr = NULL;
int oldstr_len = 0;
int substr_len = 0;
int replacement_len = 0;
newstr = strdup(string);
substr_len = strlen(substr);
replacement_len = strlen(replacement);
if (substr == NULL || replacement == NULL) {
return newstr;
}
while ((tok = strstr(newstr, substr))) {
oldstr = newstr;
oldstr_len = strlen(oldstr);
newstr = (char*)malloc(sizeof(char) * (oldstr_len - substr_len + replacement_len + 1));
if (newstr == NULL) {
free(oldstr);
return NULL;
}
memcpy(newstr, oldstr, tok - oldstr);
memcpy(newstr + (tok - oldstr), replacement, replacement_len);
memcpy(newstr + (tok - oldstr) + replacement_len, tok + substr_len, oldstr_len - substr_len - (tok - oldstr));
memset(newstr + oldstr_len - substr_len + replacement_len, 0, 1);
free(oldstr);
}
free(string);
return newstr;
}
Node* insert(Node*, char*);
void show(Node*);
// Function to insert an element to the Linked-List
Node* insert(Node *Head, char *value)
{
Node *new_string;
new_string = (Node *)malloc(sizeof(Node));
new_string->data = malloc(strlen(value)+1);
strcpy(new_string->data,value);
Node *check;
check = (Node *)malloc(sizeof(Node));
if(Head == NULL){
Head = new_string;
Head->next = NULL;
}
else{
check = Head;
while(check->next != NULL)
check = check->next;
check->next = new_string;
new_string->next = NULL;
}
return Head;
}
//Function to show the elements of the Linked-List
void show(Node *Head)
{
Node *check;
check = (Node *)malloc(sizeof(Node));
check = Head;
if (check == NULL){
return;
}
while(check != NULL) {
printf("%s", check->data);
check=check->next;
}
printf("\n");
}
//Function to check if a string finishes with a suffix
int string_ends_with(const char * str, const char * suffix)
{
int str_len = strlen(str);
int suffix_len = strlen(suffix);
return
(str_len >= suffix_len) &&
(0 == strcmp(str + (str_len-suffix_len), suffix));
}
Node *listFilesRecursively(char*, char*);
//Function to find the files in a directory based on a wildcard
Node *listFilesRecursively(char *basePath, char *suffix)
{
char path[1000];
struct dirent *dp;
DIR *dir = opendir(basePath);
Node *Head = NULL;
Node *Head_scl = NULL;
//if (!dir)
// return;
while ((dp = readdir(dir)) != NULL)
{
if (strcmp(dp->d_name, ".") != 0 && strcmp(dp->d_name, "..") != 0)
{
strcpy(path, basePath);
strcat(path, "/");
strcat(path, dp->d_name);
if (string_ends_with(path, suffix))
Head = insert(Head, path);
listFilesRecursively(path, suffix);
}
}
//show(Head);
closedir(dir);
return Head;
}
int main()
{
char path[100];
char suffix[100];
// Input path from user
// Suffix Band Sentinel-2 of Type B02_10m.tif
printf("Enter path to list files: ");
scanf("%s", path);
printf("Enter the wildcard: ");
scanf("%s", suffix);
Node *B02_head;
Node *SCL_head;
B02_head = listFilesRecursively(path, suffix);
char *suffix_scl = "SCL_10m.tif";
SCL_head = listFilesRecursively(path, suffix_scl);
show(B02_head);
show(SCL_head);
return 0;
}
包括
#包括
#包括
#包括
#包括“gdal/gdal.h”
#包括“gdal/cpl_conv.h”
#包括
#包括
//链表的节点结构
类型定义结构列表{
字符*数据;
结构nlist*next;
}节点;
//函数将字符串替换为另一个字符串
//串
char*str_替换(char*string,const char*substr,const char*replacement){
char*tok=NULL;
char*newstr=NULL;
char*oldstr=NULL;
int oldstr_len=0;
int substr_len=0;
整数替换_len=0;
newstr=strdup(字符串);
substr_len=strlen(substr);
更换=斯特伦(更换);
if(substr==NULL | | replacement==NULL){
返回新闻TR;
}
而((tok=strstrstr(newstr,substr))){
oldstr=newstr;
oldstr_len=strlen(oldstr);
newstr=(char*)malloc(sizeof(char)*(oldstr_len-substr_len+replacement_len+1));
if(newstr==NULL){
免费(oldstr);
返回NULL;
}
memcpy(newstr、oldstr、tok-o