明确比较布尔常量是否很糟糕，例如如果(b == false)在Java中?

Is it bad to explicitly compare against boolean constants e.g. if (b == false) in Java?(明确比较布尔常量是否很糟糕，例如如果(b == false)在Java中?)

问题描述

写不好:

if (b == false) //...

while (b != true) //...

总是改写更好:

if (!b) //...

while (!b) //...

大概在性能上没有区别(或者有吗?)，但是你如何权衡两者之间的明确性、简洁性、清晰性、可读性等?

Presumably there is no difference in performance (or is there?), but how do you weigh the explicitness, the conciseness, the clarity, the readability, etc between the two?

为了限制主观性，我还希望引用权威编码风格指南中的任何引用，这些引用总是更可取或何时使用.

To limit the subjectivity, I'd also appreciate any quotes from authoritative coding style guidelines over which is always preferable or which to use when.

注意:变量名b只是作为例子，还有foo和bar.

Note: the variable name b is just used as an example, ala foo and bar.

推荐答案

不一定是坏事，只是画蛇添足.此外，实际的变量名称权重很大.例如，我更喜欢 if (userIsAllowedToLogin) 上面的 if (b) 或更糟糕的 if (flag).

It's not necessarily bad, it's just superfluous. Also, the actual variable name weights a lot. I would prefer for example if (userIsAllowedToLogin) above if (b) or even worse if (flag).

至于性能问题，编译器会以任何方式对其进行优化.

As to the performance concern, the compiler optimizes it away at any way.

更新:至于权威来源，我在 Sun 编码约定，但至少 Checkstyle 有一个 SimplifyBooleanExpression 模块会对此发出警告.

Update: as to the authoritative sources, I can't find something explicitly in the Sun Coding Conventions, but at least Checkstyle has a SimplifyBooleanExpression module which would warn about that.

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