#!/usr/bin/perl
# Program to generate Random DNA set:
use strict;
use warnings;


print "\n\n Enter No. of DNA Molecules required: ";
chomp( my $number = <STDIN> );

print "\n Enter Maximum length of DNA (bases): ";
chomp( my $maxl = <STDIN> );

print "\n Enter Minimum length of DNA (bases): ";
chomp( my $minl = <STDIN> );


# An array initialized to the empty list, to store the DNA in:
# Call the subroutine to do the real job:
my @random_DNA = make_random_DNA_set( $minl, $maxl, $number );

# print the results, one per line
print "\n The DNA set containing $number DNA molecules, varying in length from $minl to $maxl bases, are:\n\n";

print map( "$_\n", @random_DNA ), "\n";

my $output = 'my RandDNA .txt';
open my $RESULT, '>', $output or die qq[Cannot open file "$output" because: $!];
print $RESULT <<RESULT;

 Randomly Generated dna:

The DNA set containing $number molecules varying in length from $minl to $maxl bases are:

@random_DNA
RESULT

exit 0;


# Subroutines
# Calling the subroutine make_random_DNA_set
sub make_random_DNA_set {
        # Collect arguments, declare variables
        my ( $minl, $maxl, $number ) = @_;
        my @set;
        # Create set of random DNA:
        for ( 1 .. $number ) {
                # find a random length between min & max
                my $length = $minl + int rand $maxl - $minl + 1;
                # add $dna fragment to @set
                push @set, make_random_DNA( $length );
                }
        return @set;
        }

# Now write the subroutine make_random_DNA:
sub make_random_DNA {
        my ( $length ) = @_;
        my @nucleotides = qw( A T G C );
        return join '', map $nucleotides[ rand @nucleotides ], 1 .. $length;
        }