Why Does -0 Exist?

While experimenting with JavaScript. I was testing around with some odd little code snippets, here are a few of my findings (to help understand how I came upon -0), While doing +[

Solution 1:

JavaScript uses IEEE 754 standard to represent numbers. From Wikipedia:

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.

The IEEE 754 standard for floating point arithmetic (presently used by most computers and programming languages that support floating point numbers) requires both +0 and −0. The zeroes can be considered as a variant of the extended real number line such that 1/−0 = −∞ and 1/+0 = +∞, division by zero is only undefined for ±0/±0 and ±∞/±∞.

From this Post

Solution 2:

It's to help determine what happens when you divide by it.

If you divide by +0, you get +Infinity. If you divide by -0, you get -Infinity. (For nonzero numerators, of course).