Here you can find the source of countBits(int n)
| Parameter | Description |
|---|---|
| n | The number whose bits should be counted |
public static int countBits(int n)
//package com.java2s; /*//from ww w .j a va 2 s. c o m * www.javagl.de - Utilities - Combinatorics * * Copyright (c) 2008-2013 Marco Hutter - http://www.javagl.de * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, * copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following * conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ public class Main { /** * A magic utility method that happens to return the number of * bits that are set to '1' in the given number. * * @param n The number whose bits should be counted * @return The number of bits that are '1' in n */ public static int countBits(int n) { int m = n - ((n >> 1) & 033333333333) - ((n >> 2) & 011111111111); return ((m + (m >> 3)) & 030707070707) % 63; } }