Linux 中 C 语言中的分段错误

Question

我正在尝试在 Linux ubuntu 中运行这个 C 编程。我遇到错误分段错误（核心转储）。我正在尝试读取包含以下格式行的文本文件：

key01 value01
key02 value02
key03 value03 

这是我的程序。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_ARY 50
int main() 
{
    int i=0;
    int numProgs=0;
    char* lines[MAX_ARY];
    char line[40];
    int j;
    char search_key[1000];
    int position=6, length=5, c = 0;
    char str[10];
    int ret=0;
    char* token;
    char* my_key;    
    FILE *file;
    file = fopen("client1.txt", "r");
    while(fgets(line, sizeof line, file)!=NULL) 
        {
            //check to be sure reading correctly
            //printf("%s", line);
            //add each filename into array of programs
            lines[i]=malloc(sizeof(line));
            strcpy(lines[i],line);
            i++;
            //count number of programs in file
            numProgs++;
        }
    //check to be sure going into array correctly 
    for (j=0 ;j<numProgs+1;j++) 
        {
            //printf("%s", lines[j])
            ;
        }
    printf("Please enter your search:");
    scanf("%s",str);

    for(i = 0; i<numProgs; i++)
        {    
            // Gettng the univ names from the list
            token = strtok(lines[i]," ");
            /* walk through other tokens */
            while( token != NULL )
                {
                    ret=strcmp(str, token);
                    printf("str=%st token=%s ret=%dn", str, token, ret);
                    token = strtok(NULL," ");
                    if(ret==0)
                        {
                            //now token should be my required token, so break here
                            break;
                        }
                }
            if (ret == 0)
                break;
        }
    printf("Required substring is: %sn", token);
    //send(token,to-server1); 
    fclose(file);
    return 0;
}

我无法修复错误。

Answer 1

我刚刚尝试了这个版本的代码（实际上它和你的代码一样，除了两个小的更改）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_ARY 50
int main()
{
    int i=0;
    int numProgs=0;
    char* lines[MAX_ARY];
    char line[40];
    int j;
    char search_key[1000];
    int position=6, length=5, c = 0;
    char str[10];
    int ret=0;
    char* token;
    char* my_key;
    FILE *file;
    file = fopen("client1.txt", "r");
    while(fgets(line, sizeof line, file)!=NULL)
    {
        //check to be sure reading correctly
        //printf("%s", line);
        //add each filename into array of programs
        lines[i]=malloc(sizeof(line));
        strcpy(lines[i],line);
        i++;
        //count number of programs in file
        numProgs++;
    }
    //check to be sure going into array correctly
    for (j=0 ;j<numProgs;j++)
    {
        printf("%s", lines[j]);
    }
    printf("Please enter your search:");
    scanf("%s",str);

    for(i = 0; i<numProgs; i++)
    {
        // Gettng the univ names from the list
        token = strtok(lines[i]," ");
        /* walk through other tokens */
        while( token != NULL )
        {
            ret=strcmp(str, token);
            printf("str=%st token=%s ret=%dn", str, token, ret);
            token = strtok(NULL," ");
            if(ret==0)
            {
                //now token should be my required token, so break here
                break;
            }
        }
        if (ret == 0)
            break;
    }
    printf("Required substring is: %sn", str);
    //send(token,to-server1);
    fclose(file);
    return 0;
}

变化 ：

1- for (j=0 ;j<numProgs+1;j++) ---> for (j=0 ;j<numProgs;j++)

2-printf("Required substring is: %sn", token); ---> printf("Required substring is: %sn", str);（如果您尝试打印令牌，它只会打印空）

结论：

您的代码工作正常，请验证文件"client1.txt"是否与您的 .c 文件存在于同一目录中。一般来说，在调用函数后进行测试是一个好习惯，例如（fopen，open，malloc ...等）如果一切顺利