I need to round a number's decimal place to a n-number

Question

I need to divide a with b and round that number to a n number of decimals. example : a = 2 b = 52 n = 5 , Solution = 0.03846. I can only use intigers!!

I've been working with decimalformat but I don't know how to make the format custom.

DecimalFormat nstevilo = new DecimalFormat("#.###");//I need to change ### to a n-number.
    if(x<y) {
    double a = x/y;
    System.out.print(nstevilo.format(a));
    }

This only outputs #.### because of the format i need to make it #.######- n times of decimal.

"string as of instruction"? what's that? you are *already* using string as input to the formatter — Sharon Ben Asher, Jun 13 '19 at 07:03
@SharonBenAsher i get the error "The method repeat(string) is undefined for the type string. — Libraa, Jun 13 '19 at 07:20
Hello Libraa. Please do not edit your title, and add SOLVED to it. Instead, either accept the answer that helped you out the most by checking the checkmark next to that answer. Or, add an answer to your own question. — TT., Jun 13 '19 at 08:01

TechFree · Accepted Answer · 2019-06-13T07:20:23.020

0

Try:

private static DecimalFormat df = new DecimalFormat("0.00000");

public static void main(String[] args)
{
        double d = 2 / (double) 52;
        System.out.println(df.format(d));

}

Also, if the number of deciamls is dynamic, you can use:

private static DecimalFormat df = new DecimalFormat();

public static void main(String[] args)
{
            df.setMaximumFractionDigits(5);
            double d = 2 / (double) 52;
            System.out.println(df.format(d));
}

edited Jun 13 '19 at 07:20

answered Jun 13 '19 at 06:50

TechFree

2,600
1
17
18

Thank you very much, the second options work perfectly – Libraa Jun 13 '19 at 07:25

score 0 · Answer 2 · answered Jun 13 '19 at 06:51

0

You can use setMaximumFractionDigits(int) to set that

Example

DecimalFormat df = new DecimalFormat();
double d = 13/7.0;
System.out.println(d); // 1.8571428571428572
System.out.println(df.format(d)); //1.857
df.setMaximunFractionDigits(4);
System.out.println(df.format(d)); //1.8571

answered Jun 13 '19 at 06:51

Yogesh Patil

908
4
14

Tried, ends up always outputting the same number of digits even if i change the 4 to 10 – Libraa Jun 13 '19 at 07:04
It works on my end. Can you paste your test code where output is same? – Yogesh Patil Jun 13 '19 at 07:16
It's okay i figured it out, sorry – Libraa Jun 13 '19 at 07:25

score -1 · Answer 3 · edited Jun 20 '20 at 09:12

-1

You can try this way:

int d = x / y; 
for (int i = 0; i <= n; i++) { 
            System.out.print(d); 
            x = x - (y * d); 
            if (x == 0) 
                break; 
            x = x * 10; 
            d = x / y; 
            if (i == 0) 
                System.out.print("."); 
        }

Details here

P.S: Make sure to handle for negative inputs

edited Jun 20 '20 at 09:12

Community

1
1

answered Jun 13 '19 at 06:50

user404

1,934
1
16
32

Does not work outputs 0.0.0.2.3 etc. – Libraa Jun 13 '19 at 06:56
@Libraa, I have updated, please check that. – user404 Jun 13 '19 at 06:56

I need to round a number's decimal place to a n-number

3 Answers3