ch04.071_prob

Perl Best Practices the source code

##############################################################################
## Code fragment (NOT RECOMMENDED) from Chapter 4 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  ##
##############################################################################


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

my $min;
my $max;
my @samples = (1..100);
my $found_target;
my $target = 55;
my $pos;

# Binary chop search...
SEARCH:
for ($min=0,$max=$#samples, $found_target=0; $min<=$max; ) {
    $pos = int(($max+$min)/2);
    my $test_val = $samples[$pos];
 
    if ($target == $test_val) {
        $found_target = 1;
        last SEARCH;
    }
    elsif ($target < $test_val) {
        $max = $pos-1;
    }
    else {
        $min = $pos+1;
    }
}

use Data::Dumper 'Dumper';
warn Dumper [ $pos, $found_target];