什么| =运算符意味着什么 [英] What |= operator means?

问题描述

此运算符的含义（| =）

用于以下示例代码

what this operator means(|=)
used in following sample code

id |= static_cast<quint32>(static_cast<quint8>(data[0] & 0x1F) << 24)

请解释这行代码。如果可能..



我的尝试：



我需要了解运营商，我之前从未使用过。

please explain this line of code. if possible..

What I have tried:

I need to know about operator, which i never used before.

推荐答案

下次尝试谷歌搜索答案。这是个简单的。你只是谷歌的C ++ | =运营商。开始阅读。



在这种情况下，它是两个运营商合二为一。这是一个按位OR操作和一个赋值，如下所示：

Next time try Googling for the answer. This is an easy one. You just Google for "C++ |= operator". Start reading.

In this case, it's two operators in one. It's a bitwise OR operation combined with an assignment, like this:

C |= 2

与

is the same as

C = C | 2

在您的示例中，等效代码为：

In your example, the equivilent code would be:

frame2send.id = frame2send.id | (data[0] & 0xff) << 24;

让我们从一个更简单的例子开始，因为属性并不总是支持这种语法。

Let's start on a more simple example, because properties do not always Support this syntax.

byte theValue= 0;

theValue|= 0x01;

的含义相同：

means the same as:

theValue= theValue | 0x01;

剩下的问题是运算符|意思是：



这意味着对两个论点中的或表示。

现在的问题是有点明智还是：

0或0是0

0或1是1

1或0是1

1或1是1

您可以在上表中看到，只要其中一个参数为1，结果为1。



现在，我假设你知道一个字节是8位，以防万一不要求谷歌。

The remaining question is what does Operator "|" means:

It means bit whise "or" of the two arguments.
Now the question is what means "bit wise or":
0 or 0 is 0
0 or 1 is 1
1 or 0 is 1
1 or 1 is 1
You can maybe see in the table above, as soon as one of the arguments is "1" the result is "1".

Now, I assume you know a byte is 8 bits, in case not ask Google for more.

Arg1       : 0000 0000
Arg2       : 0000 0001
Arg1 | Arg2: 0000 0001

依此类推

为了深入了解这一点，请问Google：

C中的位置操作 - 维基百科，免费的百科全书 [ ^ ]

每个赋值运算符都是相同的。这个

It is the same for every assignment operator. This

id |= something;

表示

means

id = id | something;

C运营商 [ ^ ]查看赋值运算符



你应该提高你对C / C ++基础知识的了解

C编程语言 - 维基百科，免费的百科全书 [ ^ ]

https://hassanolity.files.wordpress.com/2013 /11/the_c_programming_language_2.pdf [ ^ ]

http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf [ ^ ]

C Operators[^] look at assignment operators

You should sharpen your knowledge of C/C++ basics
The C Programming Language - Wikipedia, the free encyclopedia[^]
https://hassanolity.files.wordpress.com/2013/11/the_c_programming_language_2.pdf[^]
http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf[^]

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