shh2.javasrc
Class Format

Object
  |
  +--Format

public class Format

extends Object

Formatting utilities.

Author:

Mark McConnell

Constructor Summary

Format()

Method Summary

static String	round(float x, int dec_places) Given the float x, rounds it off to the nearest dec_places decimal places, if any.
static String	roundToSigFig(float x, int sig_figs) Converts the number of significant figures (sig_figs) into the appropriate number of decimal places, then passes off the work to round(float, int).

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Format

public Format()

Method Detail

round

public static String round(float x,
                           int dec_places)

Given the float x, rounds it off to the nearest dec_places decimal places, if any. Examples:

• Format.round(1.7320508, 3, true) returns 1.732
• Format.round(1.7320508, 4, true) returns 1.7321

WARNING: there will be errors if rounding x * 10^(dec_places) to the nearest integer overflows the int datatype.

Returns:

A String containing the rounded-off value.

Throws:

IllegalArgumentException - If dec_places is less than 0 (just because we haven't written that case).

roundToSigFig

public static String roundToSigFig(float x,
                                   int sig_figs)

Converts the number of significant figures (sig_figs) into the appropriate number of decimal places, then passes off the work to round(float, int).

The result is incorrect in some ways.

• Does not do any rounding to the left of the decimal point of x. For instance, roundToSigFig(1001, 3) is 1001.
• Never takes more decimal places than sig_figs. For instance, roundToSigFig(.001, 3) is .001, not .00100. This is what you want, say, when you're labeling the interval [0,1] on a chart.
• 0 goes to 0, not 0.000.