Floating point number representation, Java example [duplicate]

Question

Could you please explain, why I got next result:

when I run this:

System.out.println((0.2 - 0.1));

I got: 0.1

when I run this:

System.out.println((0.3 - 0.2));

I got: 0.09999999999999998

I know that number "0.1" doesn't have finite representation in binary, but it doesn't explain the results above. Most likely this is not about particular language but about how digits are stored in computer.

Answer 1

Java uses IEEE floating point to represent double values. It is not a precise representation, and some calculations result in tiny errors that manifest themselves in this way.