使用fgets按行读取文件，为何读完一行，下行读不出来了 - 编程论坛

#2

xuyejin2023-06-07 14:02

char u8Buff[100],u8Buff1[100] 定义

#3

xuyejin2023-06-07 14:04

文件内容是：

$ cat doorconfig.txt
door open mode = password
Off delay = 15

#4

rjsp2023-06-07 16:05

你贴个完整代码出来别人才可以调试，比如

程序代码：

#include <stdio.h>

int main( void )
{
    FILE* fd_door_cfg = fopen( "./doorconfig.txt", "r+" );
    if( fd_door_cfg )
    {
        printf("file open!\n");

        long fc = ftell( fd_door_cfg );
        printf( "%ld\n", fc );

        char u8Buff[100];
        fgets( u8Buff, 100, fd_door_cfg );
        fc = ftell( fd_door_cfg );
        printf("%ld LINE = %s\n", fc, u8Buff );

        char u8Buff1[100];
        fgets( u8Buff1, 100, fd_door_cfg );
        fc = ftell( fd_door_cfg );
        printf( "%d LINE = %s\n", fc, u8Buff1 );

        fclose( fd_door_cfg );
    }
}

#5

xuyejin2023-06-07 17:48

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

FILE *fd_door_cfg;
unsigned short door_open_mode,door_off_dly;

int main(int argc, char *argv[])
{
    int res,i;
    char u8Buff[100],u8Buff1[100],s,*ptr;
    long int fc;

    // ------------打开开门授权方式配置文件，如果不存在创建文件，并写入缺省密码开门授权
    printf("begin! \n");
    fd_door_cfg = fopen("./doorconfig.txt","r+");
    if(fd_door_cfg == NULL)
    {//如果打不开文件，那么创建文件，并写入缺省值 1 (密码)
        printf("doorconfig.txt not exist! \n");
        fd_door_cfg = fopen("./doorconfig.txt","w+");
        if(fwrite("door open mode = password\n", sizeof("door open mode = password\n"),1, fd_door_cfg) != 1)
        printf("write doorconfig.txt error! \n");
        if(fwrite("Off delay = 15\n", sizeof("Off delay = 15\n"),1 ,fd_door_cfg) != 1)
        printf("write doorconfig.txt error! \n");
        printf("doorconfig.txt creat! \n");
    }
    else
    printf("doorconfig.txt exist! \n");

    fclose(fd_door_cfg);



    fd_door_cfg = fopen("./doorconfig.txt","r+");
    printf("file open!\n");

    i = 0;
    fc = ftell(fd_door_cfg);
    printf("%d\n",fc);
    fgets(u8Buff,100,fd_door_cfg);
    fc = ftell(fd_door_cfg);
    printf("%d LINE = %s\n",fc,u8Buff);
    fgets(u8Buff1,100,fd_door_cfg);
    fc = ftell(fd_door_cfg);
    printf("%d LINE = %s\n",fc,u8Buff1);

    //{
    //    printf("LINE = %s\n",u8Buff);
    //}
    //printf("read first line = %.s\n",u8Buff);
    //fgets(&u8Buff[0],100,fd_door_cfg);
    //printf("read second line = %s\n",u8Buff);

    if(strcmp(u8Buff,"door open mode = password") == 0)
    door_open_mode = 1;
    else if(strcmp(u8Buff,"door open mode = card") == 0)
    door_open_mode = 0;
    else if(strcmp(u8Buff,"door open mode = card | password") == 0)
    door_open_mode = 2;
    else if(strcmp(u8Buff,"door open mode = card & password") == 0)
    door_open_mode = 3;
    else
    door_open_mode = 1;

    //fgets(&u8Buff[0],200,fd_door_cfg);
    //printf("read second line = %s\n",u8Buff);

    //door_off_dly = atoi(ptr);
    //printf("open mode = %x, off dly = %d\n",door_open_mode,door_off_dly);



    fclose(fd_door_cfg);



    return 0;
}

#6

xuyejin2023-06-07 17:50

运行结果如下：

begin!
doorconfig.txt exist!
file open!
0
26 LINE = door open mode = password

42 LINE =

第二行就没有输出

#7

rjsp2023-06-07 20:46

if(fwrite("door open mode = password\n", sizeof("door open mode = password\n"),1, fd_door_cfg) != 1)
if(fwrite("Off delay = 15\n", sizeof("Off delay = 15\n"),1 ,fd_door_cfg) != 1)
改为
if(fwrite("door open mode = password\n", sizeof("door open mode = password\n")-1,1, fd_door_cfg) != 1)
if(fwrite("Off delay = 15\n", sizeof("Off delay = 15\n")-1,1 ,fd_door_cfg) != 1)

字符串 "abc\n" 一共包含 5 个字符，分别是 'a', 'b', 'c', '\n', '\0'

#8

xuyejin2023-06-08 08:13

谢谢版主，我修改了下，好了，谢谢啦！

#9

xuyejin2023-06-08 08:20

编程论坛对于我这种新手来说，又多了个老师啊，

#10

hunterhuang2023-08-06 23:01

可以学习有意思的案例