Given a number, round up to the nearest power of ten times 1, 2, or 5. - Java java.lang

Java examples for java.lang:Math Calculation

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Description

Given a number, round up to the nearest power of ten times 1, 2, or 5.

Demo Code

/**//  w w w. j a  v  a 2 s. com
 * Copyright (C) 2009 - 2013 SC 4ViewSoft SRL
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;

public class Main {
    /**
     * Given a number, round up to the nearest power of ten times 1, 2, or 5.
     * 
     * @param val the number, it must be strictly positive
     */
    private static double roundUp(final double val) {
        int exponent = (int) Math.floor(Math.log10(val));
        double rval = val * Math.pow(10, -exponent);
        if (rval > 5.0) {
            rval = 10.0;
        } else if (rval > 2.0) {
            rval = 5.0;
        } else if (rval > 1.0) {
            rval = 2.0;
        }
        rval *= Math.pow(10, exponent);
        return rval;
    }
}

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