Our Prime Numbers code in Perl.
Prime Numbers Class File:
package PRIMENUMBERS;
BEGIN {
require Exporter;
# for the sake of standard
our $VERSION = 2016.12;
# Inherit from exporter to export functions and variables
our @ISA = qw(Exporter);
# Functions and variables to be exported by default
our @EXPORT_OK = qw(getPrimes);
}
use warnings;
use strict;
use POSIX qw(ceil pow); # round andlround seemed to be unavailable, so we go for 'ceil'
my ($start, $stop, $progress, $index, $square_root, $do_next_iteration);
my (@result, @list_of_primes);
# simulate an object construct
# takes two arguments -- besides its name;
# start and stop values for the range
sub new {
my $this = shift;
my $parameters = {@_};
bless $parameters, $this;
$this->_init(@_);
return $this;
}
# simulate a constructor
sub _init {
my $self = shift;
($start, $stop) = @_;
# STEP 1:
$progress = 9;
@list_of_primes = (2, 3, 5, 7);
$square_root = 0;
}
# Returns an array reference of the desired set of prime numbers
sub getPrimes {
# STEP 2:
for (; $progress <= $stop; $progress += 2) {
$do_next_iteration = 0; # a flag
# STEPS 3, 4:
# Check through already accumulated prime numbers
# to see if any is a factor of "progress".
$square_root = ceil(sqrt($progress));
$index = 0;
for (; $list_of_primes[$index] <= $square_root; $index++) {
if ($progress % $list_of_primes[$index] == 0) {
$do_next_iteration = 1;
last;
}
}
next if $do_next_iteration;
# if all checks are scaled,then "progress" is our guy.
push @list_of_primes, $progress;
}
return \@list_of_primes;
}
1;Main Class:
#!/usr/bin/perl;
use strict;
use warnings;
use PRIMENUMBERS;
# Useful variables
my ($lower_boundary, $upper_boundary, $answer);
# Use the prime numbers module/class
$lower_boundary = 3;
$upper_boundary = 7;
my $prime_list = PRIMENUMBERS->new($lower_boundary, $upper_boundary);
$answer = $prime_list->getPrimes();
print "Prime numbers between $lower_boundary and $upper_boundary are:\n@{$answer}\n";
print "\n\n";Try it out!
Elegance (0.0)
