# Division by zero floating point question

Vanitha Naidu

Greenhorn

Posts: 2

posted 11 years ago

I am going through Java 2 Sun Certification Study guide by Sierra/Bates.

On Page 163 (last paragraph) the authors discuss division by zero and state that "Floating-point numbers divided by zero return either positive or negative infinity, depending on whether or not the zero is positive or negative!"

When I tested this in code I get -infinity only when the dividend is negative regardless of whether 0(divisor) is positive or negative

i.e. -6.25/0 or -6.25/-0 is -infinity and

6.25/0 or 6.25/-0 is infinity

so the answer is dependant on the sign of the dividend and not on whether 0 is positive or negative.

Please help, is the book incorrect or am I interpreting this incorrectly.

Thanks

Vanitha

On Page 163 (last paragraph) the authors discuss division by zero and state that "Floating-point numbers divided by zero return either positive or negative infinity, depending on whether or not the zero is positive or negative!"

When I tested this in code I get -infinity only when the dividend is negative regardless of whether 0(divisor) is positive or negative

i.e. -6.25/0 or -6.25/-0 is -infinity and

6.25/0 or 6.25/-0 is infinity

so the answer is dependant on the sign of the dividend and not on whether 0 is positive or negative.

Please help, is the book incorrect or am I interpreting this incorrectly.

Thanks

Vanitha

Chris Allen

Ranch Hand

Posts: 127

posted 11 years ago

I created a small program to test the above problem. Here is the code:

The output is as follows:

Value is:-Infinity

Value is:-Infinity

Value is:Infinity

Value is:Infinity

I am guessing that your divisor is not a floating point number (either a float or double) but an integer which is accounting for the incorrect result.

The output is as follows:

Value is:-Infinity

Value is:-Infinity

Value is:Infinity

Value is:Infinity

I am guessing that your divisor is not a floating point number (either a float or double) but an integer which is accounting for the incorrect result.

Sanyev Babu

Ranch Hand

Posts: 132