Demonstrate our own version round() : Math « Development Class « Java

1. Java
2. Development Class
3. Math

Demonstrate our own version round()

         

/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */
/**
 * Demonstrate our own version round().
 * @author Ian F. Darwin, http://www.darwinsys.com/
 * @version $Id: Round.java,v 1.4 2004/03/06 22:17:32 ian Exp $
 */
public class Round {
  /** We round a number up if its fraction exceeds this threshold. */
  public static final double THRESHOLD = 0.54;
  /* 
   * Round floating values to integers.
   * @Return the closest int to the argument.
   * @param d A non-negative values to be rounded.
   */
  static int round(double d) {
    if (d < 0) {
      throw new IllegalArgumentException("Value must be non-negative");
    }
    int di = (int)Math.floor(d);  // integral value below (or ==) d
    if ((d - di) > THRESHOLD) {
      return di + 1;
    } else {
      return di;
    }
  }
  
  public static void main(String[] argv) {
    for (double d = 0.1; d<=1.0; d+=0.01) {
      System.out.println("My way:  " + d + "-> " + round(d));
      System.out.println("Math way:" + d + "-> " + Math.round(d));
    }
  }
}


           
         
    
    
    
    
    
    
    
    
  

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