从函数返回字符串数组 [英] Returning a string array from a function
问题描述
我想从函数返回一个（任意长度）字符串数组，所以
调用数组之后我就是我有一个可以访问的字符串列表。
经过多次浏览互联网后，我在这里找到了一个相关的答案（由
Eric Sosman提供）创建一个指针数组并使用
，它看起来像：
void foo（char * sptr []，int items）
{
char buff [50];
while（--items> = 0）
{
sprintf（buff，foo％d，items）;
sptr [items] = malloc（strlen（buff）+ 1）;
if（sptr [ items] == NULL）
退出（0）;
strcpy（sptr [items]，buff）;
}
}
int main（无效）
{
int total = 10;
char * p [total];
foo（p，total）;
printf（p [1]）;
返回0;
}
这是一种享受（我可以访问我的字符串，例如printf线）但是
如果我不知道我的清单要花多长时间，我会怎么做类似的事情
是什么？例如。 "总"只有在foo里面才能找到。
非常感谢，
亚当
-
Adam Richardson
Carpe Diem
" Adam" < ne ** @ snowstone.org.ukwrote in message
news：48 ************** @ snowstone.org.uk ...
我想从函数中返回一个（任意长度）字符串数组，所以
在调用数组后我有一个我可以访问的字符串列表。
经过多次浏览互联网后，我在这里找到了一个相关的答案（由
Eric Sosman）涉及创建一个指针数组并使用
，所以它看起来像：
void foo（char * sptr []，int items）
{
char buff [50];
while（--items> = 0）
{
sprintf（buff，" foo％d"，items）;
sptr [items] = malloc（strlen（buff）+ 1 ）;
if（sptr [items] == NULL）
exit（0）;
strcpy（sptr [items]，buff） ;
}
}
int main（无效）
{
int total = 10;
char * p [total];
foo（p，total）;
printf（p [1]）;
返回0;
}
这是有效的对待（我可以访问我的字符串，例如printf线）但是
如果我不知道我的清单要花多长时间，我会怎么做类似的事情
是什么？例如。 "总"只有在foo里面才能找到。
非常感谢，
Adam
char * * foo（int items）
{
char ** answer;
char buff [100];
int i;
answer = malloc（items * sizeof（char *））;
if（！answer）
goto error_exit;
/ *需要清理，不能有非空垃圾指针* /
for（i = 0; i< items; i ++）
回答[i] = 0;
for（i = 0; i< items; i ++）
{
sprintf（buff，foo％d，i）：
回答[i] = malloc（stren（buff）+ 1）;
if（！answer [i]）
转到error_exit;
strcpy（回答[i]，buff）;
}
返回答案;
error_exit：
if（answer）
for（i = 0; i< items; i ++）
免费（回答[i]）;
免费（回答）;
/ *可能打印错误信息/终止于这里* /
返回0;
}
在文章< Mt ****************************** @ bt.com> ;,
Malcolm McLean< re ******* @ btinternet.comwrote：
>" Adam" < ne ** @ snowstone.org.ukwrote in message
新闻：48 ************** @ snowstone.org.uk ...
>我想从函数中返回一个（任意长度）字符串数组，以便在调用数组后我有一个可以访问的字符串列表。
answer = malloc（items * sizeof（char *））;
if（！answer）
转到error_exit;
/ *需要清理，不能有非空垃圾指针* /
嗯。 Adam的问题并不像教科书的作业那样，你需要使用goto来降低代码质量，以便
降低对任何复制它的人的标记进行评级。
-
那时候我很年轻，但我也很朦胧。
- Christopher Priest
在消息< Wb ************************ ****** @ comcast.com>，Eric Sosman
写道：
Adam写道：
我想从一个函数返回一个（任意长度）字符串数组，所以
调用数组之后我有一个字符串列表我可以访问。
^^^^^功能
[剪辑讨论]
非常感谢您提供有用的信息。我会离开并做一些思考
关于最好的行动方案。 :)
您使用的是C99编译器吗？
是的，GCC，-std = c99。
谢谢，
Adam
-
Adam Richardson
Carpe Diem
Hi,
I''d like to return an (arbitrary length) string array from a function so
that after calling the array I''ve got a list of strings I can access.
After much perusing of the internet I found a related answer here (by
Eric Sosman) which involved creating an array of pointers and using
that, so it looks something like:
void foo(char *sptr[], int items)
{
char buff[50];
while (--items >= 0)
{
sprintf (buff, "foo%d", items);
sptr[items] = malloc(strlen(buff) + 1);
if (sptr[items] == NULL)
exit(0);
strcpy (sptr[items], buff);
}
}
int main(void)
{
int total = 10;
char *p[total];
foo(p, total);
printf(p[1]);
return 0;
}
This works a treat (I can access my strings, e.g. the printf line) but
how would I do a similar thing if I don''t know how long my list is going
to be? E.g. "total" only gets found out inside foo.
Thanks a lot,
Adam
--
Adam Richardson
Carpe Diem
"Adam" <ne**@snowstone.org.ukwrote in message
news:48**************@snowstone.org.uk...Hi,
I''d like to return an (arbitrary length) string array from a function so
that after calling the array I''ve got a list of strings I can access.
After much perusing of the internet I found a related answer here (by
Eric Sosman) which involved creating an array of pointers and using
that, so it looks something like:
void foo(char *sptr[], int items)
{
char buff[50];
while (--items >= 0)
{
sprintf (buff, "foo%d", items);
sptr[items] = malloc(strlen(buff) + 1);
if (sptr[items] == NULL)
exit(0);
strcpy (sptr[items], buff);
}
}
int main(void)
{
int total = 10;
char *p[total];
foo(p, total);
printf(p[1]);
return 0;
}
This works a treat (I can access my strings, e.g. the printf line) but
how would I do a similar thing if I don''t know how long my list is going
to be? E.g. "total" only gets found out inside foo.
Thanks a lot,
Adam
char **foo(int items)
{
char **answer;
char buff[100];
int i;
answer = malloc(items * sizeof(char *));
if(!answer)
goto error_exit;
/* needed for clean up, mustn''t have non-null garbage pointers */
for(i=0;i<items;i++)
answer[i] = 0;
for(i=0;i<items;i++)
{
sprintf(buff, "foo %d", i):
answer[i] = malloc(stren(buff) + 1);
if(!answer[i])
goto error_exit;
strcpy(answer[i], buff);
}
return answer;
error_exit:
if(answer)
for(i=0;i<items;i++)
free(answer[i]);
free(answer);
/* maybe print error message / terminate here */
return 0;
}
In article <Mt******************************@bt.com>,
Malcolm McLean <re*******@btinternet.comwrote:
>"Adam" <ne**@snowstone.org.ukwrote in message
news:48**************@snowstone.org.uk...
>I''d like to return an (arbitrary length) string array from a function so
that after calling the array I''ve got a list of strings I can access.
answer = malloc(items * sizeof(char *));
if(!answer)
goto error_exit;
/* needed for clean up, mustn''t have non-null garbage pointers */Hmmm. Adam''s question didn''t -sound- like textbook homework, that you
needed to use a goto to down-grade the code quality so as to
down-grade the marks of anyone who copied it literally.
--
I was very young in those days, but I was also rather dim.
-- Christopher Priest
In message <Wb******************************@comcast.com>, Eric Sosman
wrote:Adam wrote:I''d like to return an (arbitrary length) string array from a function so
that after calling the array I''ve got a list of strings I can access.
^^^^^ function
[snip discussion]
Thanks a lot for the helpful info. I''ll go away and do some pondering
about the best course of action. :)
Are you using a C99 compiler?Yep, GCC, -std=c99.
Thanks,
Adam
--
Adam Richardson
Carpe Diem
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