Rounding a double to a format

Hi,
I'm trying to get a result for a formula in the format of ##.##. The result for one equation, for example, is 10.637129724208375 and I want it to be 10.64 (round to the nearest tenth, pretty much).
Any suggestions?

aeternaly wrote:
I'm trying to get a result for a formula in the format of ##.##. The result for one equation, for example, is 10.637129724208375 and I want it to be 10.64 (round to the nearest tenth, pretty much).If it's just for display, look at DecimalFormat or String.format().
If you actually need to store values to two decimal places, you're generally better off using BigDecimal.
You can find the explanation why [url http://www.eason.com/library/math/floatingmath.pdf]here (the original) or [url http://floating-point-gui.de/]here (mybe a bit friendlier).
Winston

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Rounding up doubles to 2 decimal places

I'm currently rounding up a double in my program using Math.round(double)
However I want to strip any trailing zeros from the output, so:
1.235 would round to 1.24
but 1.00 would round to 1
How would I go about doing this?

Also I'm making my own function to round the doubles,
and they are returning doubles so I cannot return a
string.If they are returning doubles that the number of "trailing zeros" is irrelevant, as that is formating. Really you should keep the precision until you want to display it, then use the formatter above.
What are you doing?
I'm going to take a shot in the dark; has this got something to do with money?

Round a double value to a specific number of decimal places?

Hello,
Is there standard java function which will round a double value to a specified number of decimal places? Something like:
double d = 4.34523;
d = round(d, 2);
where d is finally assigned the value of 4.34?
Thanks!
-exits

No, because doubles hold values in binary (as do all values in a computer, of course, but there's no additional stuff to indicate decimal values).
If you want values with specific rounding rules in decimal, use java.math.BigDecimal.
If you just want to format the number with a specified number of decimal digits, use java.text.DecimalNumber.

Help needed : Formatting a double using Decimal Format

Hi Everyone,
I am having trouble formatting doubles. Basically I recieve a double and an int that represents the number of decimal places.
From this I have to round the double. This is no problem, and is carried out as follows:
public static String roundDouble(double d, int scale){
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formatter.applyPattern("########.#######");
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This work fine for me. (I use a DecimalFormatter to convert exponential in to actual). However my problem is that when my colleuge uses this method from a different locale it all goes wonky.
In my locale of UK given something like 0.92742999999999 with 4 dp I get
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formatter.applyPattern("########.#######");# before the decimal point have no effect on the format.
This work fine for me. (I use a DecimalFormatter to
convert exponential in to actual). However my problem
is that when my colleuge uses this method from a
different locale it all goes wonky.
In my locale of UK given something like
0.92742999999999 with 4 dp I get
0.9274. In his locale which is Germany, he gets
0,9274.0000The pattern for the UK should be ".#######"
The pattern for DE should be ",#######"
I assume I need to use
DecimalFormatter.applyLocalizedPattern, but what
should the pattern be?You can't hard code values into your code, use a properties file to localize your program.

Need some help in Rounding a double value to a whole number

Hey Peeps,
Need some help here, I got a method that returns a value in double after a series of calculation.
I need to know how can I round the double value, so for example,
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Hi Keerthi- Try this...
1. if the value is 62222.22222222, it rounds to 62222 and
double d = 62222.22222222;long l = (int)Math.round(d * 100); // truncatesd = l / 100.0;
double d = 62222.22222222;
System.out.println(d);
long l = (int)Math.round(d * 100);
// truncatesSystem.out.println(l);
d = l / 100.0;System.out.println(d);
for (int i = 0; i < 1000; i++)
{ d -= 0.1;}
for (int i = 0; i < 1000; i++)
{ d += 0.1;}System.out.println(d);
regards- Julie Bunavicz
Output:
62222.22222222
62222
62222.22
62222.22000000000001

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F

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What's the best way to round a double to 12 decimals?

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Rounding a double

Hi,
What's the best (and fastest since I got lots of values) way to perform a rounding on a double value?
I think what I'd like to do is half-up rounding, so when it should round up to 2 digits e.g., it should cut off the rest when the third position is a 0;1;2;3 or 4 and should add one to the second digit, when the third is one out of them: 5;6;7;8;9.
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Thanx I tried it out and I thought I had to use Math.round() the way I did. But still what happens at the conversion from an int to a double - just curious?
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Cheers Mike

Oh, classical and very typical question on this forum.
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By definition, double is an approximation. No gurantee on precision lose.
--lichu

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Regards.

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take a look at your second 'for' loop:
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System.out.println("" + input.readDouble());
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Rounding a double to a format

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