Here you can find the source of chopFractionalPart(float original, int no_of_digits )
public static final float chopFractionalPart(float original, int no_of_digits )
//package com.java2s; /* /*from w ww . ja v a2 s .c om*/ This file is part of JIV. Copyright (C) 2000, 2001 Chris A. Cocosco (crisco@bic.mni.mcgill.ca) JIV 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 2 of the License, or (at your option) any later version. JIV 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 JIV; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA, or see http://www.gnu.org/copyleft/gpl.html */ public class Main { /** used by reduceSignificantDigits() */ /*private*/ static final int[] __chopFractionalPart_lookup = { 1, 10, 100, 1000, 10000, 100000 }; /** Limitation: (original * 10^no_of_digits) has to fit in a signed integer (java integers are 32bit) */ public static final float chopFractionalPart(float original, int no_of_digits /** 0...5 */ ) { // use a lookup table for speed int mult = __chopFractionalPart_lookup[no_of_digits]; return Math.round(original * mult) / (float) mult; } }