Precision iN Java

[harbir]

Hello Guys!!!
I have a question for a precision in java.
i am using

double num=.349995953;

now the thing is that i want to round of variable "num" to two decimal places. so that the value of num become .35

I am not falimiar with how to set this precision, I wonder if any one can help me.
Regards
Harbir

[sec_ware]

Hi

A quick (ugly) way of doing this would be the following:

pseudo:

1. double num2=num*100 (since you want to round to 2 decimal places)
2. int rounded=round(num2)
3. num=rounded/100.

The code[1]:

// JDK1.0.2 
public class divers {
  public static void main(String args[]){
    divers d = new divers();
    d.testRound();
    }

  public void testRound(){
    double r = round(3.1537, 2); 
    System.out.println(r); // output is 3.15
    }

  double round(double value, int decimalPlace) {
    double power_of_ten = 1;
    while (decimalPlace-- > 0)
       power_of_ten *= 10.0;
    return Math.round(value * power_of_ten) 
       / power_of_ten;
    }
  }
 
//JDK1.1 
import java.math.*;

public class divers {
  public static void main(String args[]){
    divers d = new divers();
    d.testRound();
    }

  public void testRound(){
    double r = 3.1537;
    int decimalPlace = 2;
    BigDecimal bd = new BigDecimal(r);
    bd = bd.setScale(decimalPlace,BigDecimal.ROUND_HALF_UP);
    r = bd.doubleValue();
    System.out.println(r); // output is 3.15
    }
 }

Cheers

[1] http://www.rgagnon.com/javadetails/java-0016.html

[hypronix]

http://java.sun.com/j2se/1.5.0/docs/...berFormat.html

You need SDK 1.5.0 for this I think, maybe it works on 1.4.2 as well.

[gothic_type]

NumberFormat works on 1.4.2 as well - I've used it quite successfully before. The only thing about it is that it can be a bit annoying to set up...but I guess it's debatable whether Math.round(...) is any easier.

ac

[harbir]

Thanx Guys