round up to 5 decimal places in java?

Question

I have a Sting value contains in Exponential

class round{    
    public static void main(String args[]){
        String a ="2.4545776339999877E7";
        double roundOff = Math.round(a);
        System.out.println(roundOff);
    }
}

So i want to round off upto 5 decimal vaue. How to do it please?

To you mean 5 digits of precision, 5 digits after the decimal point, or to the nearest 1/100000th as these are all different things. Can you say what the expected result is? — Peter Lawrey, May 19 '14 at 12:05

score 1 · Answer 1 · answered May 19 '14 at 12:05

1

If you want just to output (or get some String) out of this float value you may do this:

double val = Double.valueOf(a);
String str = String.format("%.5f", val);
System.out.println (str);

Else if you really want to get double with 5 signs of precision after integer part, you may write the following:

double val = ... // the same as in the previous example
double val5Signs = Math.floor(val * 1e5) / 1e5;

answered May 19 '14 at 12:05

Dmitry Ginzburg

7,391
2
37
48

This will round to the nearest 1/100000th. – Peter Lawrey May 19 '14 at 12:06
@PeterLawrey it's what OP requesting, isn't it? – Dmitry Ginzburg May 19 '14 at 12:08
+1 It might be or the OP might expect `2.45458E7` which is different. – Peter Lawrey May 19 '14 at 12:10

score 0 · Answer 2 · answered May 19 '14 at 12:09

You can also use the Java Decimal-Formatter for Output-Purposes:

double input = Double.valueOf(a);
DecimalFormatSymbols symbol = DecimalFormatSymbols.getInstance();
symbol.setDecimalSeparator('.');
System.out.println(new DecimalFormat("#0.00000", symbol).format(input));

round up to 5 decimal places in java?

2 Answers2