指向const字符串的指针 [英] pointer to const string

问题描述

大家好，

我是初学者，我的问题是：



char * p =&之间是否有任何区别; Hello，world！" ;;

和

const char * p =" Hello，world！";

？

解决方案

//更多信息

如果我定义p& p_const函数如下：

char * p =" Hello，world！";

const char * p_const =" Hello，world！" ;;

似乎TI的编译器不允许

p_const [0] =''A'';

但是它允许

p [0] =''A'';

而MSVC6.0并不允许它们两个。

什么关于C标准？


感谢您的任何建议！

2006年12月1日23:54:56 -0800，死循环 < fo ************ @ gmail.com>

写道：

> //更多信息
如果我定义p& p_const函数如下：
char * p =" Hello，world！";
const char * p_const =" Hello，world！";
似乎是一个TI的编译器不允许
p_const [0] =''A'';
但它允许
p [0] =''A'';
并且MSVC6.0不允许它们两个。
C标准怎么样？

http：//www.c- faq.com/ansi/strlitnotconst.html


comp.lang.c常见问题列表问题11.8b

问：如果可以''修改字符串文字，为什么它们不被定义为

是const字符数组？


答：一个原因是代码中包含如此多的代码像


char * p =" Hello，world！" ;;


这些不一定是不正确的。这些行会受到

诊断消息的影响，但它实际上是后来尝试修改

p指向的问题。

另见问题1.32。


-

jay

< blockquote> Dead Loop写道：

//更多信息

如果我定义p& p_const函数如下：

char * p =" Hello，world！";

const char * p_const =" Hello，world！" ;;

似乎TI的编译器不允许

p_const [0] =''A'';

但是它允许

p [0] =''A'';

而MSVC6.0并不允许它们两个。

什么关于C标准？

修改字符串文字会导致未定义的行为。

Hi all,
I''m a beginner and my question is:
Are there any differences between
char *p = "Hello, world!";
and
const char *p = "Hello, world!";
?

解决方案

// more information
If I define p & p_const in a function as follows:
char *p = "Hello, world!";
const char *p_const = "Hello, world!";
It seems that a TI''s compiler doesn''t allow
p_const[0] = ''A'';
but it allows
p[0] = ''A'';
And MSVC6.0 doesn''t allow both of them.
What about the C standard?

Thanks for any advice!

On 1 Dec 2006 23:54:56 -0800, "Dead Loop" <fo************@gmail.com>
wrote:

>// more information
If I define p & p_const in a function as follows:
char *p = "Hello, world!";
const char *p_const = "Hello, world!";
It seems that a TI''s compiler doesn''t allow
p_const[0] = ''A'';
but it allows
p[0] = ''A'';
And MSVC6.0 doesn''t allow both of them.
What about the C standard?

http://www.c-faq.com/ansi/strlitnotconst.html

comp.lang.c FAQ list Question 11.8b
Q: If you can''t modify string literals, why aren''t they defined as
being arrays of const characters?

A: One reason is that so very much code contains lines like

char *p = "Hello, world!";

which are not necessarily incorrect. These lines would suffer the
diagnostic messages, but it''s really any later attempt to modify what
p points to which would be problems.

See also question 1.32.

--
jay

Dead Loop wrote:

// more information
If I define p & p_const in a function as follows:
char *p = "Hello, world!";
const char *p_const = "Hello, world!";
It seems that a TI''s compiler doesn''t allow
p_const[0] = ''A'';
but it allows
p[0] = ''A'';
And MSVC6.0 doesn''t allow both of them.
What about the C standard?

Modifying string literals leads to undefined behaviour.

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