哪里放一个常数？ [英] Where to place a constant?

问题描述

我有自己的字符串类，与

std :: string相比，我通常都非常喜欢。出于同样的原因，我正在努力改进它。


因为我的项目中的manny对象将包含空字符串"我认为在b / b
所有未初始化的字符串之间共享空字符串分配是个好主意。


但是我有不知道在哪里放置这个常数？ ：-S

我试过这个：


class CBL_String

{

public：

static char * strEmptyString ="" ;; //它抱怨这个...


};


如果我不在课堂规范中初始化它但是在cpp文件中我不确定

它是否在使用之前实际初始化，由其他全局CBL_String

变量...对吧？


char * CBL_String :: strEmptyString ="" ;;

建议有人吗？


-

Lasse

I have my own string class that I''m generally verry fond of compared to
std::string. For that same reason I''m trying to improve a little on it.

Since manny objects in my project will contain strings of empty size "" I
thought it would be a good idea to share en empty string allocation between
all uninitialized strings.

However I have no idea where to place this constant? :-S
I tried this:

class CBL_String
{
public:
static char * strEmptyString = ""; // it complaines about this...

};

If I do don''t initialize it in the class-spec but in a cpp file I''m not sure
that it is actually initialized before used, by some other global CBL_String
variable... right?

char *CBL_String::strEmptyString = "";
Suggestions anyone?

--
Lasse

推荐答案

2004年2月16日星期一12:23:11 +0100，Lasse Skyum < no spam>写道：

On Mon, 16 Feb 2004 12:23:11 +0100, "Lasse Skyum" <no spam> wrote:

建议任何人？

使用std :: string你会好得多。

You''d be much better off using std::string.

建议任何人？

你''使用std :: string会好得多。

You''d be much better off using std::string.

好​​吧......也许是这样，但我真的不知道为什么？ CBL_String以不同的方式帮助我进行manny

从来没有成为我程序中任何错误的来源。


std :: string是否有共享的空字符串或者它使用NULL作为

空字符串？

如果std :: string如果没有初始化也分配了一个空字符串，那么我看到

没有理由使用它...


顺便说一句，我也写了我自己的CBL_ArrayList作为向量的等价物...

ony difference是设置标志时自动收缩的能力。对于

一些奇怪的原因它在我的插入/删除基准测试中也超过了矢量，

可能只是一堆设置或其他东西。


我确定所有这些也都在Boost中（或者可能是什么样的C ++扩展）但是我已经学到了很多东西都是我自己写的。


无论如何......我只是想要一个初始化的常量:-)可能还有

与其他东西相关！


- -

Lasse

Okay... maybe so, but I don''t really se why? CBL_String helps me in manny
different ways and has never been the source of any bugs in my programs.

Does std::string have a shared empty string or maybe it uses NULL as an
empty string?
If std::string also allocated an empty string if not initialized, then I see
no reason what so ever to use it...

BTW, I''ve also written my own CBL_ArrayList as an equivalent to vector...
ony differenceis the ability to automatically shrink if a flag is set. For
some odd reason it also outperformes vector in my insert/remove benchmarks,
probably just a bunch of settings or something.

I''m sure all this is also in Boost (or whatever C++ extentions there might
be) but I''ve learned so much be writing it my self.

Anyway... I just wanted to have an initialized constant :-) Might also be
relevant for other things!

--
Lasse

Lasse Skyum< no spam>写道：

Lasse Skyum <no spam> wrote:

>建议任何人？
使用std :: string你会好得多。

>Suggestions anyone?
You''d be much better off using std::string.

好的......也许是这样，但我真的不知道为什么？

Okay... maybe so, but I don''t really se why?

仅仅因为std :: string是'标准'。使用它可以让你的代码更好地重新用于初学者。

std :: string是否有一个共享的空字符串或者它可能使用NULL作为空的
串？


这将是一个实现细节。

如果std :: string也分配了一个空字符串，如果没有初始化，那么我看到
没有理由什么如此使用它...


一个体面的std :: string实现将确保''std :: string s;''是

_really_便宜。在这种情况下我不希望任何动态分配。

顺便说一句，我也写了我自己的CBL_ArrayList作为向量的等价物...


这让我觉得比一个''新''字符串类更糟糕的想法

（可能因某些编码相关的原因而有其用途）

ony差异是能力如果设置了标志，则自动缩小。
由于某些奇怪的原因，它在我的插入/删除基准测试中也超过了矢量，可能只是一堆设置或其他东西。


很高兴看到一些最小的代码证明这些结果。

除非你放弃一些''重要''标准，否则不容易相信:: vector

特征。

我肯定这一切也在Boost中（或者可能有的C ++扩展）但是我已经我学到了很多东西。

Simply because std::string is ''the standard''. Using it makes your code
better re-usable for starters.
Does std::string have a shared empty string or maybe it uses NULL as an
empty string?
This would be an implementation detail.
If std::string also allocated an empty string if not initialized, then I see
no reason what so ever to use it...
A decent std::string implementation will make sure that ''std::string s;'' is
_really_ cheap. I would not expect any dynamic allocation in this case.
BTW, I''ve also written my own CBL_ArrayList as an equivalent to vector...
This strikes me as an even worse idea than having a ''new'' string class
(which might have its uses for certain encoding related reasons)
ony differenceis the ability to automatically shrink if a flag is set.
For some odd reason it also outperformes vector in my insert/remove
benchmarks, probably just a bunch of settings or something.
Would be nice to see some minimal code demonstrating these results.
It''s not easy to believe unless you dropped some ''important'' std::vector
characteristics.
I''m sure all this is also in Boost (or whatever C++ extentions there might
be) but I''ve learned so much be writing it my self.

学习总是重写某些标准课程的好理由。

很少尽管如此，_using_他们的理由足够了;-)


Andre''[谁也不是特别喜欢std :: string但是使用它
$ b然而，$ b]

Learning is always a good reason to re-write certain standard classes.
It is rarely a good enough reason for _using_ them, though ;-)

Andre'' [who isn''t particularly fond of std::string either but uses it
nevertheless]

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