枚举定义中的波浪号 (~) 是什么? [英] What is the tilde (~) in the enum definition?

问题描述

我总是很惊讶，即使在使用 C# 这么久之后，我仍然设法找到我不知道的东西......

I'm always surprised that even after using C# for all this time now, I still manage to find things I didn't know about...

我已经尝试在互联网上搜索此内容，但是在搜索中使用~"对我来说效果不佳，而且我在 MSDN 上也没有找到任何内容(并不是说它不存在)

I've tried searching the internet for this, but using the "~" in a search isn't working for me so well and I didn't find anything on MSDN either (not to say it isn't there)

最近看到这段代码，波浪号(~)是什么意思?

I saw this snippet of code recently, what does the tilde(~) mean?

/// <summary>
/// Enumerates the ways a customer may purchase goods.
/// </summary>
[Flags]
public enum PurchaseMethod
{   
    All = ~0,
    None =  0,
    Cash =  1,
    Check =  2,
    CreditCard =  4
}

我看到它有点惊讶，所以我试着编译它，它工作了......但我仍然不知道它的含义/作用.有什么帮助吗??

I was a little surprised to see it so I tried to compile it, and it worked... but I still don't know what it means/does. Any help??

推荐答案

~ 是一元补码运算符——它翻转其操作数的位.

~ is the unary one's complement operator -- it flips the bits of its operand.

~0 = 0xFFFFFFFF = -1

在二进制补码算法中，~x == -x-1

几乎所有从 C 中借用语法的语言都可以找到 ~ 运算符，包括 Objective-C/C++/C#/Java/Javascript.

the ~ operator can be found in pretty much any language that borrowed syntax from C, including Objective-C/C++/C#/Java/Javascript.

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