原始浮点值如何为-0.0？那是什么意思？ [英] How can a primitive float value be -0.0? What does that mean?

问题描述

一个原始的浮点值如何能够为-0.0？这是什么意思？

我可以取消这个功能吗？

当我有：

  float fl; 
  

然后 fl == -0.0 code> true ，所以 fl == 0 。但是，当我打印它时，它打印 -0.0 。

解决方案

Java使用浮点运算IEEE标准（IEEE 754），它定义了 -0.0 以及何时应该使用。
$ b

最小数字表示没有1位低于正常的有效数，被称为正数或负数零符号。它实际上是表示在0和同一符号的最小可表示的非零数字之间的范围内舍入到零的数字，这就是为什么它有一个符号，为什么它的倒数+ Inf或 - Inf还有一个标志。

你可以通过添加 0.0

  Double.toString（value + 0.0） ; 
  

请参阅：

涉及负零的操作 >

...

（-0.0）+ 0.0 - > 0.0

-
$ b

- 0.0是在浮点运算产生一个如此接近0的负浮点数而不能产生正常表示。




How come a primitive float value can be -0.0? What does that mean?
Can I cancel that feature?

When I have:

  float fl;  

Then fl == -0.0 returns true and so does fl == 0. But when I print it, it prints -0.0.

解决方案

Because Java uses the IEEE Standard for Floating-Point Arithmetic (IEEE 754) which defines -0.0 and when it should be used.

The smallest number representable has no 1 bit in the subnormal significand and is called the positive or negative zero as determined by the sign. It actually represents a rounding to zero of numbers in the range between zero and the smallest representable non-zero number of the same sign, which is why it has a sign, and why its reciprocal +Inf or -Inf also has a sign.

You can get around your specific problem by adding 0.0

e.g.

Double.toString(value + 0.0);

See: Java Floating-Point Number Intricacies

Operations Involving Negative Zero
...
(-0.0) + 0.0 -> 0.0

-

"-0.0" is produced when a floating-point operation results in a negative floating-point number so close to 0 that cannot be represented normally.

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