Java Number Round roundString(double d)

Description

Rounds the number returning a string representation of the numner

License

Open Source License

Declaration

public static String roundString(double d) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /** Rounds the number returning a string representation of the numner */
    public static String roundString(double d) {
        if (d == 0.0)
            return "" + d;
        int digits = (int) (Math.log(d) / Math.log(10));
        int n = 3 - digits;
        return fixBug("" + round(d, n), n);
    }//ww  w. j  a v a2s  .  co  m

    public static String roundString(double d, int n) {
        return fixBug("" + round(d, n), n);
    }

    private static String fixBug(String s, int n) {
        if (n >= 3) {
            int dotIndex = s.indexOf('.');
            if (dotIndex != -1)
                while ((s.charAt(s.length() - 1) == '0') && dotIndex < s.length() - 2)
                    s = s.substring(0, s.length() - 1);
        }
        // Remove the .0 part if n == 0
        if (n == 0) {
            return s.substring(0, s.indexOf("."));
        }
        return s;
    }

    /** Rounds the number to 4 significant digits */
    public static double round(double d) {
        if (d == 0.0)
            return d;
        int digits = (int) (Math.log(d) / Math.log(10));
        return round(d, 3 - digits);
    }

    /** Rounds the number to n decimal places */
    public static double round(double d, int n) {
        double shift = Math.pow(10, n);
        return ((double) ((long) (d * shift + 0.5))) / shift;
    }
}

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5. roundStr(Double value, int decimal)
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8. roundTimeStamp(long tstamp)
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