Java- Rounding up anything after 2 decimal points Not just %.2f

Question

So as the top says. I am stuck on a rather simple problem but its seems I am stuck.

Example: x = 3.141

When I use printf("x is: %.2f", x); it spits out: X is 3.14

Well to calculate state tax anything above a cent needs to be rounded up so 3.141 should be 3.15. Is there a simple printf I can modify or an additional tag I can add? Or will I need to go a round about way to calculate the additional bit?

Possible duplicate of [Java Round up Any Number](https://stackoverflow.com/questions/4540684/java-round-up-any-number) — , Apr 20 '18 at 14:02
i guess it would be a duplicate if you could math.ceil a specific decimal limit. but not exactly the same different need. — Epsilon52, Apr 20 '18 at 14:37

score 3 · Accepted Answer · answered Apr 20 '18 at 14:03

3

The easiest thing would be to add 0.005 to the number.

PS: Make sure you calculate everything strictly in BigDecimal. Using double for money is not recommended.

answered Apr 20 '18 at 14:03

J Fabian Meier

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Simple solution to a simple problem. Thankyou!! – Epsilon52 Apr 20 '18 at 14:52
If the tax was exactly 3.00, won’t this cause the tax to be displayed as 3.01? – AJNeufeld Apr 20 '18 at 16:47

score 3 · Answer 2 · answered Apr 20 '18 at 14:48

3

Instead of using printf, use a DecimalFormat with RoundingMode.CEILING:

DecimalFormat df = new DecimalFormat("#.##");
df.setRoundingMode(RoundingMode.CEILING);
String rounded = df.format(x)
System.out.printf("x is: %s", rounded);

answered Apr 20 '18 at 14:48

Mark Rotteveel

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RaffoSorr · Answer 3 · 2018-04-20T14:09:01.973

This is a possible solution:

public static float roundUp(float num, int positions) {
    int tmp = ((int)(num*Math.pow(10, positions)));
    tmp = tmp + 10 - tmp%10;
    return ((float)(tmp/Math.pow(10, positions)));
}

You can obtain what you want by calling

roundUp(num, 3);

Or if you want a less-generic method, you can as well use:

public static float roundUp(float num) {
    int tmp = ((int)(num*1000.0f));
    tmp = tmp + 10 - tmp%10;
    return ((float)(tmp/1000.0f));
}

score 0 · Answer 4 · answered Apr 20 '18 at 14:05

0

Math.ceil(x * 100) * 0.01

Avoids magic rounding numbers (do you need to add 0.9, or 0.99, or 0.999, etc)

answered Apr 20 '18 at 14:05

AJNeufeld

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Java- Rounding up anything after 2 decimal points *Not just %.2f*

4 Answers4

Java- Rounding up anything after 2 decimal points Not just %.2f