Returns true if two doubles are considered equal. - Java java.lang

Java examples for java.lang:double

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Description

Returns true if two doubles are considered equal.

Demo Code

/** Copyright (c) 2012 Memorial Sloan-Kettering Cancer Center.
 **//from  w  w  w . j a va  2 s  . c o  m
 ** This library is free software; you can redistribute it and/or modify it
 ** under the terms of the GNU Lesser General Public License as published
 ** by the Free Software Foundation; either version 2.1 of the License, or
 ** any later version.
 **
 ** This library is distributed in the hope that it will be useful, but
 ** WITHOUT ANY WARRANTY, WITHOUT EVEN THE IMPLIED WARRANTY OF
 ** MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  The software and
 ** documentation provided hereunder is on an "as is" basis, and
 ** Memorial Sloan-Kettering Cancer Center 
 ** has no obligations to provide maintenance, support,
 ** updates, enhancements or modifications.  In no event shall
 ** Memorial Sloan-Kettering Cancer Center
 ** be liable to any party for direct, indirect, special,
 ** incidental or consequential damages, including lost profits, arising
 ** out of the use of this software and its documentation, even if
 ** Memorial Sloan-Kettering Cancer Center 
 ** has been advised of the possibility of such damage.  See
 ** the GNU Lesser General Public License for more details.
 **
 ** You should have received a copy of the GNU Lesser General Public License
 ** along with this library; if not, write to the Free Software Foundation,
 ** Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 **/
//package com.java2s;

public class Main {
    private final static double EPSILON = 0.00001;

    /**
     * Returns true if two doubles are considered equal.  Tests if the absolute
     * difference between two doubles has a difference less then .00001.   This
     * should be fine when comparing prices, because prices have a precision of
     * .001.
     *
     * @param a double to compare.
     * @param b double to compare.
     * @return true true if two doubles are considered equal.
     */
    public static boolean equals(double a, double b) {
        return a == b ? true : Math.abs(a - b) < EPSILON;
    }

    /**
     * Returns true if two doubles are considered equal. Tests if the absolute
     * difference between the two doubles has a difference less then a given
     * double (epsilon). Determining the given epsilon is highly dependant on the
     * precision of the doubles that are being compared.
     *
     * @param a double to compare.
     * @param b double to compare
     * @param epsilon double which is compared to the absolute difference of two
     * doubles to determine if they are equal.
     * @return true if a is considered equal to b.
     */
    public static boolean equals(double a, double b, double epsilon) {
        return a == b ? true : Math.abs(a - b) < epsilon;
    }
}

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