2个问题 [英] 2 style questions

问题描述

1.

我正和某人讨论，我认为这只是宗教信仰。

我们正在开发一些软件，他正在查看我的代码。

我使用if（指针）来测试NULL的指针。他说必须是

（p！= NULL）。

参数是它更具可读性，如果（p）不可移植。

我说第一个是样式问题，我认为如果（p）更可读

并且第二个是完全错误的。


那么，他对可移植性问题是对的吗？是否（p）不严格正确

C代码？


2.

然后我开始查看他的代码和什么我注意到他非常

经常做这样的事情：


char * func（char ** out）

{

* out = malloc（100）;

返回malloc（10）;

}


这也可能是一个风格问题，但它是一种风格，它很容易引入错误（实际上我发现了一些）

甚至如果您不知道

函数的内部结构，则更容易引入错误。那么，您如何看待这种风格？

1.
I was having a discussion with somebody and I think it''s just religious.
We are developing some software and he was looking through my code.
I use if (pointer) to test a pointer for NULL. He says it must be if
(p!=NULL).
The arguments are that it''s more readable and that if (p) is not portable.
I said the first is a style issue and that I think if(p) is more readable
and that the second is plain wrong.

So, is he right about the portability issue? is if (p) not strictly correct
C code?

2.
Then I started looking through his code and what I noticed that he very
often does things like this:

char *func(char **out)
{
*out = malloc(100);
return malloc(10);
}

This might also be a style issue, but it''s a style where it''s very easy to
introduce bugs (and indeed I found a few)
and even more easy to introduce bugs if you don''t know the internals of the
function. So, what do you think about this style?

推荐答案

" Sander" < [e-mail]>写道：

"Sander" <[e-mail]> writes:

1.
我正在与某人进行讨论，我认为这只是宗教信仰。
我们正在开发一些软件，他正在寻找通过我的代码。
我使用if（指针）来测试NULL的指针。他说必须是
（p！= NULL）。


这两个测试是等价的。

参数是它更具可读性，如果（p）不可移植。


后者不是这样的：`if（p）''对于任何指针来说都相当于`if（p

！= NULL）'' p。

2.
然后我开始查看他的代码以及我注意到他经常做这样的事情：

char * func（char ** out）
{
* out = malloc（100）;
返回malloc（10）;
}

这也可能是一个风格问题，但它是一种风格，它很容易引入错误（事实上我发现了一些）

1.
I was having a discussion with somebody and I think it''s just religious.
We are developing some software and he was looking through my code.
I use if (pointer) to test a pointer for NULL. He says it must be if
(p!=NULL).
These two tests are equivalent.
The arguments are that it''s more readable and that if (p) is
not portable.
The latter is not true: `if (p)'' is portably equivalent to `if (p
!= NULL)'' for any pointer p.
2.
Then I started looking through his code and what I noticed that he very
often does things like this:

char *func(char **out)
{
*out = malloc(100);
return malloc(10);
}

This might also be a style issue, but it''s a style where it''s very easy to
introduce bugs (and indeed I found a few)

它至少看起来很可疑。

-

大笔资金倾向于解除我可能遇到的任何顾忌。

- - Stephan Wilms

It at least looks suspicious.
--
"Large amounts of money tend to quench any scruples I might be having."
-- Stephan Wilms

Sander写道：

Sander wrote:

1.
我正和某人讨论，我认为只是虔诚的。
我们正在开发一些软件，他正在查看我的代码。
我使用if（指针）来测试一个指针为NULL。他说必须是
（p！= NULL）。


我更喜欢***后者，if（p！= NULL）

参数是它更具可读性


我同意这一点。

和if（p）不可携带。


然而，这是无稽之谈。

我说第一个是样式问题，我认为如果（p）更具可读性
而第二个是完全错误的。


你是对的。我不同意你的风格选择，但它只是一种风格

选择。

那么，他对可移植性问题是否正确？


不，但他对风格选择是正确的。 :-)

是否（p）不严格正确的C代码？


没关系。


断言（p）但是，不是（除非你有C99编译器）。 />
2.
然后我开始查看他的代码以及我注意到他经常做这样的事情：

char * func（char * * out）
{out /> * out = malloc（100）;
返回malloc（10）;
}


EEK！这应该做什么？

这也可能是一个风格问题，但它是一种非常容易引入错误的风格（事实上我发现了一些如果你不知道这个功能的内部结构，那么就更容易引入错误了。所以，你怎么看待这种风格？

1.
I was having a discussion with somebody and I think it''s just religious.
We are developing some software and he was looking through my code.
I use if (pointer) to test a pointer for NULL. He says it must be if
(p!=NULL).
I ***prefer*** the latter, if(p != NULL)
The arguments are that it''s more readable
I agree with this.
and that if (p) is not portable.
This, however, is nonsense.
I said the first is a style issue and that I think if(p) is more readable
and that the second is plain wrong.
You are correct. I disagree with your style choice, but it is simply a style
choice.

So, is he right about the portability issue?
No. But he''s right about the style choice. :-)
is if (p) not strictly
correct C code?
It''s fine.

assert(p), however, is not (unless you have a C99 compiler).

2.
Then I started looking through his code and what I noticed that he very
often does things like this:

char *func(char **out)
{
*out = malloc(100);
return malloc(10);
}
EEK! What is this supposed to do?
This might also be a style issue, but it''s a style where it''s very easy to
introduce bugs (and indeed I found a few)
and even more easy to introduce bugs if you don''t know the internals of
the function. So, what do you think about this style?

我认为这是可怕的。具体来说，我认为你向我们展示的func（）是可怕的。我碰巧同意if（p！= NULL）是一种非常明智的方式

来呈现代码。我更喜欢保留if（x）的情况，其中x很明显是布尔意图，例如


int Split（vector * v，char * s， int WantDelimiters）

{

char * left = s;

char * right = left;

while（ *左）

{

if（WantDelimiters）

{


等

-

Richard Heathfield： bi****@eton.powernet.co .uk

Usenet是一个奇怪的地方。 - Dennis M Ritchie，1999年7月29日。

C FAQ： http://www.eskimo.com/~scs/C-faq/top.html

K& R答案，C书等：< a rel =nofollowhref =http://users.powernet.co.uk/etontarget =_ blank> http://users.powernet.co.uk/eton

I think it''s ghastly. Specifically, I think the func() you showed us is
ghastly. I happen to agree with if(p != NULL) as being a very sensible way
to present the code. I prefer to reserve if(x) for situations where x is
clearly of Boolean intent, e.g.

int Split(vector *v, char *s, int WantDelimiters)
{
char *left = s;
char *right = left;
while(*left)
{
if(WantDelimiters)
{

etc
--
Richard Heathfield : bi****@eton.powernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton

*这样说起Sander< [e-mail]>：


你好，

* Thus spoke Sander <[e-mail]>:

Hallo,

我使用if（指针）来测试NULL的指针。他说必须是
（p！= NULL）。


不过。但出于可读性原因，他可能更喜欢它。很多程序员

我知道它认为它是一种很好的编程风格。


（我的标准版本现在不可用，但是：）

| C中的每个指针类型都有一个特殊值，称为/ null指针/，

|这与该类型的每个有效指针不同，后者比较了

|等于空指针常量，它转换为空指针

|其他指针类型，其值为false用于

|时布尔上下文。 / null指针常量在C中是任何整数

|值为0的常量表达式，或者这样的表达式转换为类型

| void *。

（Harbinson / Steele）

参数是它更具可读性，如果（p）不可移植。


我用？if（！p）？如果（p ==（void *）0），if（p == int *）0），你可以进一步遇到喜欢使用

的程序员。 。

我说第一个是样式问题，我认为如果（p）更具可读性，那么第二个是完全错误的。


正如我之前所说，我也喜欢速记符号，但可能会有更多人在这一点上不同意。

char * func（char ** out）
{
* out = malloc（100）;
返回malloc（10）;
}

所以，您如何看待这种风格？

I use if (pointer) to test a pointer for NULL. He says it must be if
(p!=NULL).
No. But he might prefer it for readability reasons. Many programmers
that I know consider it as good programming style.

(My version of the standard is not available right now, but:)
| Every pointer type in C has a special value called a /null pointer/,
| which is different from every valid pointer of that type, which compares
| equal to a null pointer constant, which converts to the null pointers of
| other pointer types, and which has the value "false" when used in a
| boolean context. The /null pointer constant" in C is any integer
| constant expression with the value 0, or such an expression cast to type
| void*.
(Harbinson/Steele)
The arguments are that it''s more readable and that if (p) is not portable.
I use ?if(!p)? and you may further meet programmers that like to use
if(p==0), if(p==(void*)0), if(p== int*)0)...
I said the first is a style issue and that I think if(p) is more readable
and that the second is plain wrong.
As I said before I prefer the shorthand notation too, but there might be
more people that disagree on this point.
char *func(char **out)
{
*out = malloc(100);
return malloc(10);
}

So, what do you think about this style?

No.

Wolfgang。

-

" Erfahrungen - das sind die vernarbten Wunden unserer Dummheit。"

- John Osborne

No.
Wolfgang.
--
"Erfahrungen -- das sind die vernarbten Wunden unserer Dummheit."
-- John Osborne

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