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Round off a value

 
Greenhorn
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Hi

How do we round off a value to 6 decimal places and display it in a jsp?

Seb
 
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Hi seb,

Get the value in to one float or double depand upon the value. import the util.* in the jsp page and use the desired function to round of the value .

Float f ;
f= 12.546465469546f;
Know the f value using the round function in java.util pack
i think this can help you.
 
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Not really a JSP question so moving along to the Java Intermediate forum.
 
Ranch Hand
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Originally posted by Christie George:
Hi

How do we round off a value to 6 decimal places and display it in a jsp?

Seb


Since you are doing this for display purposes, you should probably use java.text.NumberFormat. This class has methods to specify the number of digits before and after the decimal point. See the above link to the appropriate Javadocs for details.

Layne
 
Greenhorn
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There is a little trick - you multiply by 10^n where n is the number of decimal points you want, add 0.5, take integer, and divide result by 10^n. E.g. try this,

public class Rounder {
public static void main(String[] args) {
double n = 6; //no. of decimal places
double x = 123.12345678901234; //no. to be rounded
double y = (int)(x*Math.pow(10,n)+0.5)/Math.pow(10,n);
System.out.println(y); //result
}
}

Hope this helps,
Alastair
 
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Originally posted by Alastair Calderwood:
There is a little trick...

Since float and double values are not stored in decimal notation, they are only approximations of decimal values. While this trick will get you close, it won't be exact.

If you just want to round for display, use NumberFormat Layne said. If you need to use the rounded number in an exact calculation, you should use java.math.BigDecimal. The latter represents an exact decimal value to a very high number of decimal places and precision.
 
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