#!/usr/bin/perl

#
#  BCE Project 11
#

use strict;
use warnings;

my $Directory = '/usr/bin'; # Any directory containing files will do 
my %Fhash;                  # Numbered file list hash
my @Farray;                 # Array of found files
my $Itemcount = 0;          # Count of files found
my $File;                   #
my $Pagelen = 20;           # Page length (Number of items to print)
my $Input;                  #

sub printlist
{
  my %Thash;
  my $Start = $_[0];
  my $End = $_[1];
  my $Item;

  if ($End > $Itemcount) {
    $End = $Itemcount;
  }
  %Thash = map { $_ => $Fhash{$_} } $Start .. $End;
  foreach $Item (sort{$a <=> $b} keys %Thash) {
    printf "%s :%s\n", $Item, $Thash{$Item};
  }
}

opendir(DIR, $Directory) || die "can't opendir $Directory: $!";
@Farray = grep { -f "$Directory/$_" } readdir(DIR);
closedir DIR;

# Create serialized hash of the files...
foreach $File (sort sort{$b cmp $a} @Farray) {
  $Fhash{ ++$Itemcount } = "$Directory/$File";
}

print "Itemcount=", $Itemcount, "\n";

while (1) {
  print "Enter number: ";
  my $Input = <STDIN>;
  chomp $Input;
  if ( $Input =~ m/^q/ ) {  # q to quit
    last;
  }
  printlist $Input, $Input + $Pagelen - 1;
}
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