Formatting double to 2 decimals doesn't work

Question

I want to round this double:

3.499999999999999

to:

3.50

And I already used these two methods:

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Answer 1

Did you try replacing the 0's with #'s?

DecimalFormat df = new DecimalFormat("#.##"); System.out.println(df.format(input));

According to here the # will be resolved to 0 if the digit is absent

Answer 2

You can use the printf formatting which may be simpler.

System.out.printf("%.2f%n", 3.5);

prints

3.50

Answer 3

Your first solution is really, really close. Just do this:

    DecimalFormat df = new DecimalFormat("0.00");
    System.out.println(df.format(input));

The reason your version doesn't work is that you're taking the input double, formatting it as a String with 2dp, but then converting it back to a double. System.out.println is then printing the double as it always would, with no special decimal-place rules.

Answer 4

You can use Precision class of apache commons-math

double result = Precision.round(3.499999999999999, 2);