How to remove trailing zero from a double?

Question

My program is supposed to calculate change:

double purchaseAmount = Double.parseDouble(s1);
double amountGiven = Double.parseDouble(s2);
double change = purchaseAmount - amountGiven;
JOptionPane.showMessageDialog(null, change);

String result = "Change consists of:";

My change is counted in bills and coins. But once I get to the coins, which are double:

double quarters = 0;
if (change >= .25) {
    quarters = change / .25;
    change = change - quarters * .25;
    result = result + quarters + "quarters";
    change = change - quarters % .25;
}

The result is giving me a trailing .0 for instance instead of telling me my change is 1 twenty 2 quarters. I get 1 twenty 2.0 quarters. I've tried almost everything, BigDecimal, NumberFormat DecimalFormat(##.###) I already have a String in the program and would not know how to add another.

You should not try to do exact calculations (which you probably want to do when talking about money) using floating point types. — merryprankster, Sep 18 '14 at 06:23
Given that you can't have a fractional number of quarters, why are you storing that in a `double` anyway? (Your line of `change = change - quarters % .25;` looks dubious to me, too...) I would actually suggest that you change the value from dollars to cents to start with, and do *everything* in integer arithmetic after that. It'll make life much simpler. — Jon Skeet, Sep 18 '14 at 06:23
`result + quarters + "quarters"` <-- the `quarters` value should be formatted to a string there according to the desired rules; using an `int` might be sufficient to "solve" this issue, as such does not contain fractional information to start. — user2864740, Sep 18 '14 at 06:23
@merryprankster: Using floating point probably isn't too bad in itself - it's using *binary* floating point that causes problems. Using `BigDecimal` would be okay (if handled carefully in terms of division etc). — Jon Skeet, Sep 18 '14 at 06:25
Also check out this: [Why not use Double or Float to represent currency?](https://stackoverflow.com/questions/3730019/why-not-use-double-or-float-to-represent-currency) — icza, Sep 18 '14 at 06:28

score 0 · Answer 1 · answered Sep 18 '14 at 06:23

0

You shouldn't use floats to store monetary values. Use BigDecimal instead.
And then use NumberFormat to format the results for output.

answered Sep 18 '14 at 06:23

jwenting

5,505
2
25
30

score 0 · Accepted Answer · answered Sep 18 '14 at 06:24

0

Try to convert the double value into integer or use integer for your conversions (double will give you floating values)

 result = result + ((int) quarters) + "quarters";

or can use Math.round() function to round the values ..

answered Sep 18 '14 at 06:24

Sampath Kumar

4,433
2
27
42

How to remove trailing zero from a double?

2 Answers2