ch04.075_best

来自「Perl Best Practices the source code」· 075_BEST 代码 · 共 53 行

##############################################################################
##   Code fragment (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 (do{$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];


my $name = 'Tim Burners-Lee';
sub check_name { return 1; }

print 'Sir ',
      do{ check_name($name); $name; },
      ', KCMG';