How to round the double value to 2 decimal points? [duplicate]

This question already has answers here: Closed 10 years ago开发者_如何学Go.

Possible Duplicate:

round double to two decimal places in java

I want to round up the double value upto 2 decimal points.

for example: I have double d=2; and the result should be result =2.00

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Math.round(number*100.0)/100.0;

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double RoundTo2Decimals(double val) {
            DecimalFormat df2 = new DecimalFormat("###.##");
        return Double.valueOf(df2.format(val));
}

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There's no difference in internal representation between 2 and 2.00. You can use Math.round to round a value to the nearest integer - to make that round to 2 decimal places you could multiply by 100, round, and then divide by 100, but you shouldn't expect the result to be exactly 2dps, due to the nature of binary floating point arithmetic.

If you're only interested in formatting a value to two decimal places, look at DecimalFormat - if you're interested in a number of decimal places while calculating you should really be using BigDecimal. That way you'll know that you really are dealing with decimal digits, rather than "the nearest available double value".

Another option you may want to consider if you're always dealing with two decimal places is to store the value as a long or BigInteger, knowing that it's exactly 100 times the "real" value - effectively storing cents instead of dollars, for example.

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import java.text.DecimalFormat;

public class RoundTest {
    public static void main(String[] args) {
        double i = 2;    
        DecimalFormat twoDForm = new DecimalFormat("#.00");
        System.out.println(twoDForm.format(i));
        double j=3.1;
        System.out.println(twoDForm.format(j));
        double k=4.144456;
        System.out.println(twoDForm.format(k));
    }
}

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I guess that you need a formatted output.

System.out.printf("%.2f",d);

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you can also use this code

public static double roundToDecimals(double d, int c)  
{   
   int temp = (int)(d * Math.pow(10 , c));  
   return ((double)temp)/Math.pow(10 , c);  
}

It gives you control of how many numbers after the point are needed.

d = number to round;   
c = number of decimal places  

think it will be helpful

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This would do it.

     public static void main(String[] args) {
        double d = 12.349678;
        int r = (int) Math.round(d*100);
        double f = r / 100.0;
       System.out.println(f);
     }

You can short this method, it's easy to understand that's why I have written like this.

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public static double addDoubles(double a, double b) {
        BigDecimal A = new BigDecimal(a + "");
        BigDecimal B = new BigDecimal(b + "");
        return A.add(B).setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
    }