数组大小为0 [英] Array with size 0

问题描述

今天，我顺便定义的一维是0大小的二维数组，但是我的编译器并没有抱怨。我发现其中指出，这是合法的，至少在海湾合作委员会的情况下，以下内容：

Today I incidentally defined a two dimensional array with the size of one dimension being 0, however my compiler did not complain. I found the following which states that this is legal, at least in the case of gcc:

零长度的6.17阵列

不过，我对这个用法两个问题：

However, I have two questions on this usage:

首先，这被视为良好的编程习惯？如果是这样，那么当我们应该使用它在现实世界中？

First, is this considered as good programming practice? If so, then when should we use it in real world?

二，我所定义的数组是二维的，以0大小的一维。这是同为一维的情况下？例如，

Second, the array I defined was two dimensional, with 0 size for one dimension. Is this the same as the one dimensional case? For example,

int s[0]
int s[0][100]
int s[100][0]

他们全部在存储器和用于编译器？

Are they all the same in the memory and for the compiler?

编辑：回复格雷格：我使用的编译器是gcc 4.4.5。我的针对此问题的意图是不编译依赖性的，但是如果存在将是有益的任何编译特定怪癖太：）

Reply to Greg: The compiler I am using is gcc 4.4.5. My intention for this problem is not compiler-dependent, however if there are any compiler specific quirks that would be helpful too:)

在此先感谢！

推荐答案

在C ++中是非法的声明长度为零的数组。因此，它通常不认为是你绑你的code到一个特定的编译器扩展一个很好的做法。动态调整阵列的许多用途更好地与容器类代替，如的std ::矢量。

In C++ it is illegal to declare an array of zero length. As such it is not normally considered a good practice as you are tying your code to a particular compiler extension. Many uses of dynamically sized arrays are better replaced with a container class such as std::vector.

ISO / IEC 14882 2003 8.3.4 / 1：

ISO/IEC 14882:2003 8.3.4/1:

如果在恒前pression 的（5.19）是present，它应是一个整型常量前pression其值应大于零。

If the constant-expression (5.19) is present, it shall be an integral constant expression and its value shall be greater than zero.

不过，您可以动态地分配零长度的数组与新[] 。

However, you can dynamically allocate an array of zero length with new[].

ISO / IEC 14882 2003 5.3.4 / 6：

ISO/IEC 14882:2003 5.3.4/6:

在直接新的说明符的前pression 的应具有与非负值整数或枚举类型（3.9.1）。

The expression in a direct-new-declarator shall have integral or enumeration type (3.9.1) with a non-negative value.

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