Returns the next bigger number that's a power of 2. - Java java.lang

Java examples for java.lang:Math Number

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Description

Returns the next bigger number that's a power of 2.

Demo Code

/*//w  w  w.j  av  a  2 s.  co  m
 *   This program 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 program 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 program.  If not, see <http://www.gnu.org/licenses/>.
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        int n = 2;
        System.out.println(nextPowerOf2(n));
    }

    /**
     * Returns the next bigger number that's a power of 2. If the number is
     * already a power of 2 then this will be returned. The number will be at
     * least 2^2.
     *
     * @param n      the number to start from
     * @return      the next bigger number
     */
    public static int nextPowerOf2(int n) {
        int exp;

        exp = (int) StrictMath
                .ceil(StrictMath.log(n) / StrictMath.log(2.0));
        exp = StrictMath.max(2, exp);

        return (int) StrictMath.pow(2, exp);
    }
}

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