#!/usr/bin/perl
use warnings;
use strict;
## Perl script to create all possible combinations of A,T,G & C 
# of varying lengths:
print"\n This program will generate all possible combinations of A,T,G & C:";
print"\n Enter the length of words you want (say 2 or 3 etc.): ";
 my $num=<STDIN>;my $four=4;
 chomp $num;
 my $no_combi=$four**$num;
 print"\n Total Number of Combinations= $no_combi\n";
my $combi_2l=". . .????";
my $combi_3l=". . .????";
print"\n All possible combinations of 2-letter words: ???$combi_2l\n";
print"\n All possible combinations of 3-letter words: ???$combi_3l\n";
exit;