Why does division be negative zero returns positive infinity in Java?

Question

When I divide a positive double by negative zero, the result returns positive infinity.

double d = 10.0 / -0;

But when I divide a negative double by positive zero, the result returns negative infinity.

double d = -10.0 / 0;

Can someone explain this behavior ? Shouldn't the both operations return negative infinity ?

I think I know why the code will not throw an ArithmeticException because we are dealing with double data type. I am curious to know as to why we have this weird behavior when dividing with negative zero. — Abascus, Jun 24 '21 at 14:43
Have you checked the [second answer?](https://stackoverflow.com/questions/14137989/java-division-by-zero-doesnt-throw-an-arithmeticexception-why#answer-14138032) — samabcde, Jun 24 '21 at 14:46

score 2 · Accepted Answer · answered Jun 24 '21 at 14:42

2

As far as I am aware, there isn't actually a negative integer zero in the Java specification due to the two's complement representation used, which is clarified in answer to this question. Therefore -0 as an integer is just an unsigned 0.

If you run this test with floating point numbers, it performs as you expected:

double d = 10.0 / -0.0; // -Infinity

So the issue isn't with your logic, just your test.

answered Jun 24 '21 at 14:42

Henry Twist

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But why does `-0.0 == 0.0` return `true` ? – Gautham M Jun 24 '21 at 14:51
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Maybe [this](https://stackoverflow.com/q/24238293/7804477) explains if anyone has the above same doubt. – Gautham M Jun 24 '21 at 14:55

Why does division be negative zero returns positive infinity in Java?

1 Answers1