Returns true if the given double value will be rounded to zero - Java java.lang

Java examples for java.lang:double

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Description

Returns true if the given double value will be rounded to zero

Demo Code

/*//from   www.  ja v  a  2  s.co  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 {
    private static final double[] POWERS_OF_TEN_DOUBLE = new double[30];

    /**
     * Returns true if the given source value will be rounded to zero
     *
     * @param source the source value to round
     * @param decimals the decimals to round at (use if abs(source) ≥ 1.0)
     * @param precision the precision to round at (use if abs(source) < 1.0)
     * @return true if the source value will be rounded to zero
     */
    private static boolean isRoundedToZero(double source, int decimals,
            int precision) {
        // Use 4.999999999999999 instead of 5 since in some cases, 5.0 / 1eN > 5e-N (e.g. for N = 37, 42, 45, 66, ...)
        return source == 0.0
                || Math.abs(source) < 4.999999999999999 / tenPowDouble(Math
                        .max(decimals, precision) + 1);
    }

    private static double tenPowDouble(int n) {
        assert n >= 0;
        return n < POWERS_OF_TEN_DOUBLE.length ? POWERS_OF_TEN_DOUBLE[n]
                : Math.pow(10, n);
    }
}

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