我可以使用指针访问多维数组？ [英] Can I access multidimensional array using a pointer?

问题描述

这参考，在C似乎以下行为是不确定的。

From this reference, In C it seems the following behavior is undefined.

int my_array[100][50];
int *p = my_array[0];
p[50]; // UB

有没有C ++ 03或C ++ 11，证实了这一点？

Is there a reference in C++03 or C++11 which confirms this?

推荐答案

在是+运算符的描述。你可以不解除引用用C该指针，因为它是一个过去的端指针用于第一子阵列。在C ++中这是目前合法的，因为指针的百分点的一个有效的整数（点关系到在第3节的地方定义）。然而，在这两个标准将超过50收益率不确定的行为。

Yes in the description of the + operator. You may not dereference that pointer in C because it is a past the end pointer for the first subarray. In C++ this currently is legal because the pointer points to a valid integer (the points to relation is defined somewhere in clause 3). However in both standards adding more than 50 yields undefined behavior.

一个DR最近发送到C关于解引用这种有效凭空指针可以取消引用的规则++委员会，所以我不会依赖这一点。

A DR was recently sent to the c++ committee about the rule that dereferencing such "valid out of thin air" pointers may be dereferenced, so i would not rely on that.

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