如何从头开始截断char字符串并用C或C ++中的其他字符替换chars instring？ [英] How to truncate char string fromt beginning and replace chars instring by other chars in C or C++?

问题描述

我有一个从ctime_r返回的日期时间字符串，它是

格式，如" Wed Jun 30 21 ：49：08 1993\\\
\ 0"，有26个字符

包括最后终止字符''\ 0''，我想删除

工作日信息是周三。在这里，我也想

用_替换空格char。并删除\ n焦炭。我没有知道如何从开始截断字符串或​​者用一个字符串替换一些字符

而不使用循环通过一个字符串



字符串的一个字符。我使用下面的代码来实现

替换 "通过_并删除了最后一个\ n char，没有

但即便如此，我仍然没有得到我喜欢的内容。下面是代码我

写道：

#include< time.h>

#include< stdio.h>


int main（无效）

{

time_t ltime;

char buf [50];


//获取时间

时间（& ltime）;


// ctime_r返回的日期时间字符串格式为

//Wed Jun 30 21:49:08 1993\\\
\ 0

printf（"时间：％ s"，ctime_r（& ltime，buf））;


//替换 "和：在日期时间字符串中

//由_"

buf [7] =" _" ;; // ，第18行

buf [10] =" _" ;; // ，第19行

buf [13] =" _" ;; //"："，第20行

buf [16] =" _" ;; //"："，第21行

buf [19] =" _" ;; // "，第22行

buf [24] =" \0" ;; //删除最后的\ n字符，第23行

// printf新的datetimestring

printf（"时间是：％s"， （bf）;


}


当我用gcc编写它时，我收到了以下警告：


test_ctimer.c：在函数`main''：

test_ctimer.c：18：警告：赋值从指针生成整数

没有演员

和第19到23行的警告也一样。


当我运行它时，我得到了：


时间是： 2008年8月7日星期四15:02:32

时间是：星期四8XX 7X15X02X32X2008Z


有人可以帮助我吗？我在互联网上搜索了它似乎C / /
库没有从头开始截断的功能？并且它还没有替换字符的功能。
也没有功能。我应该用
来使用循环吗？


非常感谢您的帮助。


Hongyu

Hi,

I have a datetime char string returned from ctime_r, and it is in the
format like ""Wed Jun 30 21:49:08 1993\n\0", which has 26 chars
including the last terminate char ''\0'', and i would like to remove the
weekday information that is "Wed" here, and I also would like to
replace the spaces char by "_" and also remove the "\n" char. I didn''t
know how to truncate the string from beginning or replace some chars
in a string with another chars without using a loop through one char
by one char of the string. I used the below code to achieve
replacement of " " by "_" and also removed the last "\n" char, without
considering removing the first 4 chars i.e. weekday information yet.
But even this I still didn''t get what i like. Below is the code i
wrote:
#include <time.h>
#include <stdio.h>

int main(void)
{
time_t ltime;
char buf[50];

// Get the time
time(&ltime);

// The datetime string returned by ctime_r is in the format
// of "Wed Jun 30 21:49:08 1993\n\0"
printf("The time is: %s", ctime_r(&ltime, buf));

// replace the " " and ":" in the datetime string
// by "_"
buf[7] = "_"; // " ", line 18
buf[10] = "_"; // " ", line 19
buf[13] = "_"; // ":", line 20
buf[16] = "_"; // ":", line 21
buf[19] = "_"; // " ", line 22
buf[24] = "\0"; // remove the last \n char, line 23

// printf the new datetimestring
printf("The time is: %s", buf);

}

When I complied it with gcc, i got the below warning:

test_ctimer.c: In function `main'':
test_ctimer.c:18: warning: assignment makes integer from pointer
without a cast
and same warning for line 19 to 23 too.

When I run it, I got:

The time is: Thu Aug 7 15:02:32 2008
The time is: Thu AugX 7X15X02X32X2008Z

Can anyone kindly help me? I searched on the internet and it seems C
library doesn''t have a function to truncate from the beginning? and it
also doesn''t have a function for characher replacement. Should I have
to use a loop?

Thanks a lot for the help in advance.

Hongyu

推荐答案

Hongyu写道：

Hongyu wrote:

我有一个从ctime_r返回的日期时间字符串，它是

格式，如&Wed; Wed Jun 30 21:49:08 1993\\\
\ 0，它有26个字符

，包括最后一个终止字符''\0''，我想删除

工作日信息，即Wed。在这里，我也想

用_替换空格char。并删除\ n焦炭。我没有知道如何从开始截断字符串或​​者用一个字符串替换一些字符

而不使用循环通过一个字符串



字符串的一个字符。我使用下面的代码来实现

替换 "通过_并删除了最后一个\ n char，没有

但即便如此，我仍然没有得到我喜欢的内容。下面是代码我

写道：


#include< time.h>

#include< stdio.h> ;


int main（无效）

{

time_t ltime;

char buf [50 ];


//获取时间

时间（& ltime）;


//日期时间ctime_r返回的字符串格式为

//Wed Jun 30 21:49:08 1993\\\
\ 0

printf（&时间是：％s"，ctime_r（& ltime，buf））;


//替换 "和：在日期时间字符串中

//由_"

buf [7] =" _" ;; // "，第18行

Hi,

I have a datetime char string returned from ctime_r, and it is in the
format like ""Wed Jun 30 21:49:08 1993\n\0", which has 26 chars
including the last terminate char ''\0'', and i would like to remove the
weekday information that is "Wed" here, and I also would like to
replace the spaces char by "_" and also remove the "\n" char. I didn''t
know how to truncate the string from beginning or replace some chars
in a string with another chars without using a loop through one char
by one char of the string. I used the below code to achieve
replacement of " " by "_" and also removed the last "\n" char, without
considering removing the first 4 chars i.e. weekday information yet.
But even this I still didn''t get what i like. Below is the code i
wrote:
#include <time.h>
#include <stdio.h>

int main(void)
{
time_t ltime;
char buf[50];

// Get the time
time(&ltime);

// The datetime string returned by ctime_r is in the format
// of "Wed Jun 30 21:49:08 1993\n\0"
printf("The time is: %s", ctime_r(&ltime, buf));

// replace the " " and ":" in the datetime string
// by "_"
buf[7] = "_"; // " ", line 18

对于单个符号，您需要使用单引号：


buf [7] =' '_'';


（无处不在）。

For a single symbol you need to use single quotes:

buf[7] = ''_'';

(same everywhere).

buf [10] =" _" ;; // ，第19行

buf [13] =" _" ;; //"："，第20行

buf [16] =" _" ;; //"："，第21行

buf [19] =" _" ;; // "，第22行

buf [24] =" \0" ;; //删除最后的\ n字符，第23行

// printf新的datetimestring

printf（"时间是：％s"， （bf）;


}

[..]

buf[10] = "_"; // " ", line 19
buf[13] = "_"; // ":", line 20
buf[16] = "_"; // ":", line 21
buf[19] = "_"; // " ", line 22
buf[24] = "\0"; // remove the last \n char, line 23

// printf the new datetimestring
printf("The time is: %s", buf);

}
[..]

V

-

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V
--
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8月7日，3：31 * pm，Victor Bazarov< v.Abaza ... @ comAcast.netwrote：

On Aug 7, 3:31*pm, Victor Bazarov <[e-mail]:

Hongyu写道：

Hongyu wrote:

Hi,

I有一个从ctime_r，*返回的日期时间字符串，它是

格式，如  1993年3月30日星期三21:49:08，有26个字符

包括最后一个终止字符''\ 0''，我想删除

工作日信息，即周三。在这里，我也想

用_替换空格char。并删除\ n焦炭。我没有知道如何从开头*截断字符串或​​者用一个字符串替换一些字符

而不使用循环通过一个字符
字符串的一个字符串。我使用下面的代码来实现

替换 "通过_并删除了最后一个\ n char，没有

但即便如此，我仍然没有得到我喜欢的内容。下面是代码我

写道：

I have a datetime char string returned from ctime_r, *and it is in the
format like ""Wed Jun 30 21:49:08 1993\n\0", which has 26 chars
including the last terminate char ''\0'', and i would like to remove the
weekday information that is "Wed" here, and I also would like to
replace the spaces char by "_" and also remove the "\n" char. I didn''t
know how to truncate the string from beginning *or replace some chars
in a string with another chars without using a loop through one char
by one char of the string. I used the below code to achieve
replacement of " " by "_" and also removed the last "\n" char, without
considering removing the first 4 chars i.e. weekday information yet.
But even this I still didn''t get what i like. Below is the code i
wrote:

#include< time.h>

#include< stdio.h>

#include <time.h>
#include <stdio.h>

int main（void）

{

* * time_t ltime;

* * char buf [50];

int main(void)
{
* *time_t ltime;
* *char buf[50];

* * //获取时间

* * time（& ltime）;

* *// Get the time
* *time(&ltime);

* * // ctime_r返回的日期时间字符串格式为

* * //Wed Jun 30 21:49:08 1993 \\\
\ 0"

* * printf（"时间是：％s"，ctime_r（& ltime，buf））;

* *// The datetime string returned by ctime_r is in the format
* *// of "Wed Jun 30 21:49:08 1993\n\0"
* *printf("The time is: %s", ctime_r(&ltime, buf));

* * //替换 "和：在日期时间字符串中

* * //由_"

* * buf [7] =" _" ;; * // "，第18行

* *// replace the " " and ":" in the datetime string
* *// by "_"
* *buf[7] = "_"; *// " ", line 18

对于单个符号，您需要使用单引号：


* * * buf [7 ] =''_'';


（无处不在）。

For a single symbol you need to use single quotes:

* * *buf[7] = ''_'';

(same everywhere).

* * buf [10] =" _英寸; // ，第19行

* * buf [13] =" _" ;; //"："，第20行

* * buf [16] =" _" ;; //"："，第21行

* * buf [19] =" _" ;; // ，第22行

* * buf [24] =" \0" ;; //删除最后一个\ n字符，第23行

* *buf[10] = "_"; // " ", line 19
* *buf[13] = "_"; // ":", line 20
* *buf[16] = "_"; // ":", line 21
* *buf[19] = "_"; // " ", line 22
* *buf[24] = "\0"; // remove the last \n char, line 23

* * // printf新的datetimestring

* * printf（时间是：％s，buf）;

* *// printf the new datetimestring
* *printf("The time is: %s", buf);

}

[..]

}
[..]

V

-

请在通过电子邮件回复时删除资金''A'

我不回复热门帖子回复，请不要问 - 隐藏引用的文字 -


- 显示引用的文字 -

V
--
Please remove capital ''A''s when replying by e-mail
I do not respond to top-posted replies, please don''t ask- Hide quoted text -

- Show quoted text -

非常感谢提示帮助，维克多。有效！编译器

错误消失，空格被'' - ''取代。你能告诉我如何删除字符串开头的字符吗？以及如何
删除字符串中的字符，因为我在字符串中还有一个空格

字符串并想删除它。我尝试使用如下：

buf [0] =''''，但编译错误如：test_ctimer.c：18：12：空

字符常量


非常感谢。

Thanks a lot for the prompty help, Victor. It worked! The compiler
errors disappered and the space was replaced by ''-''. Can you also tell
me how to remove the chars in the beginning of the string? and how to
remove a char inside the string, because i have one more space inside
the string and would like to remove it. I tried to use like:
buf[0]='''', but got compiler errors like: test_ctimer.c:18:12: empty
character constant

Thanks a lot.

Hongyu写道：

Hongyu wrote:

[ ..]你能告诉

我如何删除字符串开头的字符？以及如何
删除字符串中的字符，因为我在字符串中还有一个空格

字符串并想删除它。我尝试使用如下：

buf [0] =''''，但编译错误如：test_ctimer.c：18：12：空

字符常量

[..] Can you also tell
me how to remove the chars in the beginning of the string? and how to
remove a char inside the string, because i have one more space inside
the string and would like to remove it. I tried to use like:
buf[0]='''', but got compiler errors like: test_ctimer.c:18:12: empty
character constant

关于''memmove''函数的RTFM。它应该与重叠范围一起工作。

你可以记住部分字符串本身，IIRC。


V

-

请在通过电子邮件回复时删除资金''A'

我没有回复最热门的回复，请不要问

RTFM about ''memmove'' function. It should work with overlapping ranges.
You can ''memmove'' part of the string over itself, IIRC.

V
--
Please remove capital ''A''s when replying by e-mail
I do not respond to top-posted replies, please don''t ask

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