[英]Array syntax vs. pointer syntax in C function parameters
I understand how arrays decay to pointers. 我理解数组如何衰减到指针。 I understand that, for the compiler, this: 我明白,对于编译器,这个:
void foo(int *arg1);
is 100% equivalent to this: 是100%相当于:
void foo(int arg1[]);
Should one style be preferred over the other? 一种风格应该优先于另一种吗? I want to be consistent, but I'm having a hard time justifying either decision. 我希望保持一致,但我很难为两种决定辩护。
Although int main(int argc, char *argv[])
and int main(int argc, char **argv)
are the same, the former seems to be much more common (correct me if I'm wrong). 虽然int main(int argc, char *argv[])
和int main(int argc, char **argv)
是相同的,但前者似乎更常见(如果我错了,请纠正我)。
I would recommend against using the []
syntax for function parameters. 我建议不要使用函数参数的[]
语法。
The one argument in favour of using []
is that it implies, in a self-documenting way, that the pointer is expected to point to more than one thing. 支持使用[]
的一个论点是,它以自我记录的方式暗示指针应指向多个事物。 For example: 例如:
void swap(int *x, int *y)
double average(int vals[], int n)
But then why is char *
always used for strings rather than char []
? 但是为什么char *
总是用于字符串而不是char []
? I'd rather be consistent and always use *
. 我宁愿保持一致,也总是使用*
。
Some people like to const
everything they possibly can, including pass-by-value parameters. 有些人喜欢const
他们可能做的一切,包括传值参数。 The syntax for that when using []
(available only in C99) is less intuitive and probably less well-known: 使用[]
时的语法(仅在C99中可用)不太直观,可能不太为人所知:
const char *const *const words
vs. const char *const words[const]
const char *const *const words
vs. const char *const words[const]
Although I do consider that final const
to be overkill, in any case. 虽然我确实认为最终的const
有点矫枉过正,无论如何。
Furthermore, the way that arrays decay is not completely intuitive. 此外,阵列衰减的方式并不完全直观。 In particular, it is not applied recursively ( char words[][]
doesn't work). 特别是,它不是递归应用的 ( char words[][]
不起作用)。 Especially when you start throwing in more indirection, the []
syntax just causes confusion. 特别是当你开始抛出更多的间接时, []
语法只会引起混淆。 IMO it is better to always use pointer syntax rather than pretending that an array is passed as an argument. IMO最好总是使用指针语法而不是假装数组作为参数传递。
More information: http://c-faq.com/~scs/cgi-bin/faqcat.cgi?sec=aryptr#aryptrparam . 更多信息: http : //c-faq.com/~scs/cgi-bin/faqcat.cgi?sec = aaryptr #aryptrparam 。
Except for char*
, I use Type array[N]
, where N is some number or a defined constant, when the passed item conceptually is an array (ie, it contains N>1 elements), Type * pointer
when the passed item is a pointer to exactly one object. 除了char*
,我使用Type array[N]
,其中N是某个数字或定义的常量,当传递的项目在概念上是一个数组时(即,它包含N> 1个元素),当传递的项目Type * pointer
, Type * pointer
指向一个对象的指针。
I tend to use std::vector
if the array is of a variable size. 如果数组的大小可变,我倾向于使用std::vector
。 C99's concept of variable sized arrays is not available in C++. C99的可变大小数组的概念在C ++中不可用。
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