具有两个连续运算符的 Java 数学
我最近正在调试一个问题，结果比预期大得多。我本来打算写的是：
y += height + rowHeight * 2;
我写的是
y += height * + rowHeight * 2;
我没有立即看到错误，因为显然 * + 是 Java 中的有效运算符，或者至少是 Android java 中的有效运算符。我以前从未听说过这件事，也不知道这意味着什么。
作为一个实验，我发现它的通用形式是，作为正则表达式 [*/%][+-]*
它看起来像某种形式的波兰表示法，但我不知道 Java 支持这样的。
那么...我在哪里可以找到有关该运算符的文档，它到底意味着什么？
I was recently debugging a problem where a result was much larger than expected. What I had intended to write was:
y += height + rowHeight * 2;
What I had written was
y += height * + rowHeight * 2;
I didn't see the error right away because, apparently * + is a valid operator in Java, or at least Android java. I've never heard anything about this before, and I have no idea what it means.
As an experiment, I found that the generalized form of this is, as a regex [*/%][+-]*
It looks like some form of polish notation, but I was unaware that Java supported such.
So... where would I find documentation about this operator, and what, exactly, does it mean?
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它使用一元加运算符 - 所以它是这样的：
举一个看起来一点也不奇怪的例子，但使用一元减而不是一元加：
希望更有意义:)
It's using the unary plus operator - so it's like this:
To give an example which wouldn't look odd at all, but using unary minus instead of unary plus:
Hopefully that makes more sense :)
+这里只是一个正号（一元运算符）。你可以这样重写：在java中这样写也是有效的：
+is just a positive sign here (a unary operator). You can re-write it like:It is also valid to write this in java:
编译器将表达式视为运算符
y += 高度 * (+ rowHeight) * 2;The compiler is treating the expression as operator as
y += height * (+ rowHeight) * 2;+和-也是一元运算符，否则你无法编写如下内容：Both
+and-are unary operators as well, otherwise you couldn't write things like: