Problem multiplying a double

Question

Hi All,
I have some code where I do something like
for (int i=0;i<11;i++) {
double currentValue = i * 0.01;
System.out.println(currentValue);
The result is
0.09
0.19
0.29
0.39
0.49
0.59
0.690000000000001
0.79
etc.....
How can I prevent the extra decimal points.
I know I could just cat the value to a string and
watch the lenght, then if its too long I can substring
out 4 chars. But I was wondering if I can prevent the
calculation frmo doing this.
Thanks,
Pat

Answer 1

Ok here is the fix, I think people should always post the fix.
Dont forget to import java.text.DecimalFormat
Here is the actual code. The stuff I posted earlier was
a simple example. The actual code is a program that
graphs a curve trace of a diode.
         for (int i=0; i < points.size(); i++) {
            g.fillRect(i*4+1,12,1,5);
            point = (Point)points.get(i);
            if (point.x%10 == 0) g.fillRect(i*4+1,6,1,11);
            double currentStep = i * currentStepValue;
            DecimalFormat df = new DecimalFormat("##0.000");
            if (point.x%10 == 0) {
               g.drawString(""+df.format(currentStep),i*4+1,10);
      }The part that fixes the precision problem is
DecimalFormat df = new DecimalFormat("##0.000");
g.drawString(""+df.format(currentStep),i*4+1,10);
or in the simple example I used the fix is :
for (int i=0;i<11;i++) {
   double currentValue = i * 0.01;
   DecimalFormat df = new DecimalFormat("##0.000");
   System.out.println(df.format(currentStep);
}I hope this helps someone :)
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