Rounding price number in java

Question

I'm new to java programming. I would like to round up a price to the nearest 2 decimal places with a multiple of 5.

Eg.

38.80 stays the same.
38.81 to 38.80.
38.82 to 38.80.
38.83 to 38.85.
38.84 to 38.85.
38.85 stays the same.
38.86 to 38.85.
38.87 to 38.85.
38.88 to 38.90.
38.89 to 38.90.
38.90 stays the same.

I tried the provided duplicates but they come out only to 1 decimal place. Eg. 38.82 to 38.8.

This is my code:

import java.text.DecimalFormat;

public class RoundUp {

    public static void main(String[] args){
        DecimalFormat df = new DecimalFormat("#.##");
        double num = 38.84;
        System.out.println(df.format(Math.round(num*10.00)/10.00));
    }
}

I have looked into other model answers by experts in this web but none of them really answer my question. Setting into 2 decimal places, I'm using DemicalFormat. That I know, but rounding the number, let's say 38.83 to 38.85 and 38.87 to 38.90 is what I really want. It is a rounding system that my country is using. Can check it out here.

**

This question has been answer by @Mureinik double rounded = Math.round(num * 100.0 / 5.0) * 5.0 / 100.0;

**

You have 2 separate problems here... probably should have been two questions? (1) You want to round to 1 decimal place, **except** when the second decimal place is a 5. That's not a normal way to round, so no, your code isn't going to do that—you're just calling the library function `Math.round()`, which of course is going to do something more normal. (2) You want to **print** your number with 2 decimal places, and it's not doing that for you. — Dan Getz, Jun 04 '15 at 05:43
if I dont use Math.round(), do you have any suggestion? Sorry to say but this rounding system exist in my country.. so jz gotta follow right? — Wilz5363, Jun 05 '15 at 11:59
It's the sentence near the bottom that says that 38.87 goes to 38.90 that confused me about your rounding system. I understand now, with your edit showing that 38.87 goes to 38.85. You're rounding to the nearest 0.05. — Dan Getz, Jun 05 '15 at 16:27

score 1 · Answer 1 · answered Jun 04 '15 at 05:39

1

I would recommend you to use BigDecimal instead of double when you are dealing with money.

And then it would be like

BigDecimal value = new BigDecimal(38.84);
value = value.setScale(2, BigDecimal.ROUND_HALF_UP)

You can refer Javadocs for ROUND_HALF_UP and setScale

answered Jun 04 '15 at 05:39

Rahul Tripathi

168,305
31
280
331

Hi Rahul, thanks for your recommendation. Totally appreciate it. But slight problem here... when i tried to use your code.. it doesn't round up.. – Wilz5363 Jun 05 '15 at 12:00
@Wilz5363:- Can yo utry with: `value = value.setScale(2, BigDecimal.ROUND_HALF_EVEN)` – Rahul Tripathi Jun 05 '15 at 12:03
nope....still remain as 38.84 @Rahul – Wilz5363 Jun 05 '15 at 12:04
@Wilz5363:- And what about 38.87? – Rahul Tripathi Jun 05 '15 at 12:05
:- this the code i used.. BigDecimal value = new BigDecimal(38.84); value = value.setScale(2, BigDecimal.ROUND_HALF_DOWN); System.out.println(value); – Wilz5363 Jun 05 '15 at 12:05
:- it doesnt change anything...sorry man.. – Wilz5363 Jun 05 '15 at 12:07
@Wilz5363:- Dont be sorry. Try with `BigDecimal value = new BigDecimal(38.84); value = value.setScale(2, BigDecimal.ROUND_DOWN); System.out.println(value);` – Rahul Tripathi Jun 05 '15 at 12:10
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/79779/discussion-between-wilz5363-and-rahul-tripathi). – Wilz5363 Jun 05 '15 at 12:11

Rounding price number in java

1 Answers1