Re: Strange results when adding two double primitives - Java 1.5.0_04

From:
adwords@pulpjava.com
Newsgroups:
comp.lang.java.programmer
Date:
13 Oct 2006 06:20:08 -0700
Message-ID:
<1160745608.179341.127370@b28g2000cwb.googlegroups.com>
Precision on extremely long floats, and some calculations, end up with
strange results. This isn't uncommon. Classes such as BigDecimal can
help avoid some of these issues.

-Cameron McKenzie www.pulpjava.com www.examscam.com www.scja.com

Check out my new SCJA certification guides and mock exam questions at
www.scja.com

Chris Brat wrote:

Hi,

I've found this little oddity in the application I'm working on where
the result of adding two double primitives gives a result that either
has an extra 0.0000000000000002 or it is 0.0000000000000001 less than
the expected result.

This sample app illustrates it.

Does anyone know why this happens ?

Thanks
Chris

public class A {

    public static void main (String[] args){
        double a = 67.41;
        double b = 51.85;
        double result = a + b;

        // I get 119.25999999999999
        System.out.println(result);

        a = 1.01;
        b = 2.02;
        result = a + b;

        // I get 3.0300000000000002
        System.out.println(result);

        a = 1.100;
        b = 2.103;

        result = a + b;
        // 3.2030000000000003
        System.out.println(result);
    }
}

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