x =& v和** = v是否等效？ [英] Are `x = &v` and `*x = v` equivalent?

问题描述

int * x;
int v = 7;

给出此代码，
1有什么区别。 x =& v 和
2。 * x = v ？
我了解在两种情况下， * x 包含 7 ，但 x 是否在两种情况下都包含 v 的内存位置？如果不是，在情况1和2中 x 包含什么，这是两者之间唯一的显着区别吗？

Given this code, what is the difference between 1. x = &v , and 2. *x = v ? I understand that in both cases, *x contains 7 but does x contain memory location of v in both cases? If not, what does x contain in cases 1 and 2, and is this the only significant difference between the two?

推荐答案

给出以下语句：

int v = 7; 

v 在内存中有一些位置。这样做：

v has some location in memory. Doing:

x = &v;

将指向 x v 的位置，实际上 * x 的位置值将为 7 。

will "point" x to the memory location of v, and indeed *x will have the value 7.

但是，在此语句中：

*x = v;

您将 v 的值存储在 x 指向的地址。但是 x 是 not 指向有效的内存地址，因此该语句调用了未定义的行为。

you are storing the value of v at the address pointed at by x. But x is not pointing at a valid memory address, and so this statement invokes undefined behavior.

所以要回答您的问题，否，这2条语句不相等。

So to answer your question, no, the 2 statements are not equivalent.

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