convert a speed measurement from one scale to another - Java java.lang

Java examples for java.lang:Math Convert

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Description

convert a speed measurement from one scale to another

Demo Code

/*//ww w  .  ja v a2 s .  co m
 * Copyright (C) 2012, 2013 The MaGDAA Project
 *
 * This file is part of the MaGDAA Library Software
 *
 * MaGDAA Library Software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This source code 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this source code; 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 {
    public static void main(String[] argv) throws Exception {
        float speed = 2.45678f;
        int fromScale = 2;
        int toScale = 2;
        System.out.println(convertSpeed(speed, fromScale, toScale));
    }

    /**
     * constant to define the kilometers per hour speed scale
     */
    public static final int KPH = 10;
    /**
     * constant to define the miles per hour speed scale
     */
    public static final int MPH = 11;

    /**
     * convert a speed measurement from one scale to another
     * @param speed the speed measurement to convert
     * @param fromScale the from scale, as defined by one of the speed related constants in this class
     * @param toScale the to scale, as defined by one of the speed related constants in this class
     * @return the converted speed measurement
     * @throws IllegalArgumentException if an invalid scale is provided
     */
    public static float convertSpeed(float speed, int fromScale, int toScale) {
        switch (fromScale) {
        case KPH:
            // convert from kilometers per hour
            switch (toScale) {
            case MPH:
                return convertFromKphToMph(speed);
            default:
                throw new IllegalArgumentException("invalid toScale");
            }
        case MPH:
            // convert from miles per hour
            switch (toScale) {
            case KPH:
                return convertFromMphToKph(speed);
            default:
                throw new IllegalArgumentException("invalid toScale");
            }
        default:
            throw new IllegalArgumentException("invalid fromScale");
        }
    }

    private static float convertFromKphToMph(float kph) {
        float conversionFactor = 1.609344f;
        return kph / conversionFactor;
    }

    private static float convertFromMphToKph(float mph) {
        float conversionFactor = 1.609344f;
        return mph * conversionFactor;
    }
}

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