Decimal places formating in java based on variable from user

Question

In java: I have some number and a number of desired decimal places in a variable (e.g. choosen by user), and I need to print it.

myNumber = 3.987654;
numberOfDecimalPlaces = 4;

I dont want to do it like

System.out.printf( "%.4f", myNumber);

but I need to use VARIABLE numberOfDecimalPlaces instead.

Thanks a lot

Possible duplicate of [How to round a number to n decimal places in Java](http://stackoverflow.com/questions/153724/how-to-round-a-number-to-n-decimal-places-in-java) — InbetweenWeekends, Nov 02 '15 at 15:03

score 0 · Accepted Answer · answered Nov 02 '15 at 14:55

0

Just create the format string using numberOfDecimalPlaces:

System.out.printf( "%." + numberOfDecimalPlaces + 'f', myNumber);

answered Nov 02 '15 at 14:55

wero

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@VivekSingh That's what he wanted to do. He said he doesn't want it to use a static number but wants it dynamically changing. This applies perfectly. +1 – Uma Kanth Nov 02 '15 at 15:01
I go for this aswell even if I posted NumberFormat example – Petter Friberg Nov 02 '15 at 15:03

score 0 · Answer 2 · answered Nov 02 '15 at 15:02

Can't understand why @wero is not a good answer but if you don't like to use System.out. maybe this..

NumberFormat nf = NumberFormat.getNumberInstance();
nf.setMaximumFractionDigits(numberOfDecimalPlaces);
nf.setMinimumFractionDigits(numberOfDecimalPlaces);
String toPrint = nf.format(myNumber);

Madushan Perera · Answer 3 · 2015-11-02T15:09:59.290

-1

You can try with this method :

//value is your input number and places for required decimal places

public static double function(double value, int places) {

    if (places < 0) {
        throw new IllegalArgumentException();
    }

    long factor = (long) Math.pow(10, places);
    value = value * factor;
    long tmp = Math.round(value);
    return (double) tmp / factor;
}

edited Nov 02 '15 at 15:09

answered Nov 02 '15 at 15:00

Madushan Perera

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Decimal places formating in java based on variable from user

3 Answers3