use warnings;
use strict;

# findfiles -input [-nd -na ] data [-nc -nd] modem apps -des "finding files" -r 1000
# "finding files" altered to finding_files for test purposes 
our @ARGV = qw(-input -nd -na data -nc -nd modem apps -des finding_files -r 1000);

use Data::Dumper;
use GetOpt::Std;

my %args = ('-input' => [{}],
            '-des'   => [{}],
            '-r'     => [{}]);
            
my $active_arg = 0;

for my $arg (@ARGV) {

    if (substr($arg,0,1) eq '-') {
    
        if (exists $args{$arg}) {
            $active_arg = $arg
        }
        elsif ($active_arg) {
            $args{$active_arg}[0]{$arg} = undef
        }
        else {
            die "Invalid argument(1): $arg"
        }
    }    
    else {
    
        if ($active_arg) {
            push @{$args{$active_arg}},$arg
        }
        else {
            
            die "Invalid argument(2): $arg"
        }
    
    }

}

print Dumper(\%args),"\n";

##</code><code>##

$VAR1 = {
          '-r' => [
                    {},
                    '1000'
                  ],
          '-des' => [
                      {},
                      'finding_files'
                    ],
          '-input' => [
                        {
                          '-nc' => undef,
                          '-nd' => undef,
                          '-na' => undef
                        },
                        'data',
                        'modem',
                        'apps'
                      ]
        };