ch19.002_best_ex19.2

Perl Best Practices the source code

##############################################################################
##   Example 19.2 (Recommended) from Chapter 19 of "Perl Best Practices"    ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


#  Example 19-2. Creating a fast C-based rounding subroutine using Inline::C


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;

use Inline C => q{
    int 
    rounded(double arg) {
        /* Round towards zero... */
        if (arg > 0.0)      { return floor(arg + 0.5); } 
        else if (arg < 0.0) { return ceil(arg - 0.5);  }
        else                { return 0;                }
    }
};
 
use IO::Prompt;

while (my $num = prompt -num => 'Enter a number: ') {
    print rounded($num), "\n";
}