#!/usr/bin/perl

print "To get the range of numbers \n";
print "Enter the range to see expansion \n";
chomp($range=<STDIN>);
print "The range from subroutine is :",join("==>",&get_numbers_from_ranges($range)),"\n";


sub get_numbers_from_ranges {
    my $spec = shift;

    my %numbers;
    foreach my $x ( split ',', $spec ) {
        $x =~ s/\s*//g;
        if ( $x =~ /(\d+)-(\d+)/ ) {
            $numbers{$_} = undef for $1 .. $2;
        }
        else {
            $numbers{$x} = undef;
        }
    }
    # subtracting every element by one because these are used in arrays i.e. 1st element in array index is 0
    #return map { $_ - 1 } sort { $a <=> $b } keys %numbers;
    return map { $_ - 1 } keys %numbers;
}