javascript - 同时具有正零和负零(+0，也写为0和-0)的目的是什么？

Question

根据 ECMAScript 6.0 规范:

...there is both a positive zero and a negative zero. For brevity, these values are also referred to for expository purposes by the symbols +0 and -0, respectively. (Note that these two different zero Number values are produced by the program expressions +0 (or simply 0) and -0.)

因此，+0 和 -0 是不同的数值，但它们被视为相等。我已经检查过 -0 === +0 等于 true。

我认为这只是数字在内存中存储方式的产物，并且这些值没有任何好处/目的/用途。

我说得对吗？

此外，维基百科指出:

while the two zero representations behave as equal under numeric comparisons, they yield different results in some operations

JavaScript中有这样的操作吗？

Answer 1

这是数字如何在内存中存储、表示和处理的问题，特别是对于浮点运算。

Signed zero is zero with an associated sign. In ordinary arithmetic, −0 = +0 = 0. However, in computing, some number representations allow for the existence of two zeros, often denoted by −0 (negative zero) and +0 (positive zero). This occurs in some signed number representations for integers, and in most floating point number representations. The number 0 is usually encoded as +0, but can be represented by either +0 or −0.

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