# ******************************************************
# *
# * Name:         prg-calc-primes-v1.pl
# *
# * Design Phase:
# *     Author:   John Miner
# *     Date:     05/10/2012
# *     Purpose:  Logging to file and event logs.
# *
# ******************************************************

#
# Algorithm: 
#

# 1 - Read in program arguement (N)
# 2 - Write arguement N to log file
# 3 - Write 2 & 3 as first two primes to result file
# 4 - Set found prime count = 2
# 5 - For M = 4 to N
# 6 - For O = 2 to SQRT(M)
# 7 - If M modulus O = 0, then non-prime
# 8 - Otherwise, write prime number to result file
# 9 - Increment found prime counter
# 10 - Write total number of primes & elapsed time to log file
# 11 - Display total number of primes & elapsed time to crt


# ~   
# Setup 
# ~

# Declare all variables
use strict;

# Include defined module (CPAN)
use Date::Calc qw(:all);

# Constants 
my $nl = "\n";
my $del = ',';


#
#  IsPrime() - determine if a number > 0 is prime
#

sub IsPrime()
{
   # get the input parameter
   my ($var) = @_; 
  
   # not a prime
   if ($var == 1)
   {
       return 0;
   };
   
   # a prime number
   if ($var == 2)
   {
       return 1;
   };
       
   # trial division
   for (my $cnt = 2; $cnt <= (sqrt($var) + 1); $cnt++) 
   {
       if (($var % $cnt) == 0)
       {
           return 0;
       };
   };

   # number is prime
   return 1;
};


#
#  StorePrimes() - calculate primes from 2 to n
#

sub StorePrimes()
{
   # variables
   my $line = '';
   my $found = 0;

   # get input parameter
   my ($var) = @_; 

   # open the text file
   open(TXT, '>c:\\perl-depot\\primes\\primes.csv');

   # header info - write out data
   $line = 'line no' . $del . 'prim no' . $nl;
   print TXT $line;

   # 1st prime - write out data
   $line = '1' . $del . '2' . $nl;
   print TXT $line;

   # 2nd prime - write out data
   $line = '2' . $del . '3' . $nl;
   print TXT $line;
 
   # find prime numbers
   $found = 2;
   for (my $cnt = 4; $cnt <= $var; $cnt++) 
   {      
       # found a prime by trial division?
       if (&IsPrime($cnt) == 1)
       {
           # increment found
           $found++;
           
           # prime info - write out data
           $line = $found . $del . $cnt . $nl;
           print TXT $line;
       };       
   };
   
   # close text file
   close(TXT);
   
   # return count
   return $found;
}


# ~   
# Step 1
# ~

# local variables
my $max1 = 0;
my $found1 = 0;
my $total1 = 0;

# Read in argv
if ($#ARGV + 1 != 1 ) 
{
    print 'Usage: ' . $nl;
    print '    prg-calc-primes-v1 <max integer>' . $nl;
    print ' ' . $nl;
    exit;
};
$max1 = $ARGV[0];

# get full time (y,m,d,  h,m,s, dy,dw,ds)
my @clock1 = System_Clock();

# Display message (crt)
print 'Starting program' . $nl;
print localtime() . $nl;
print ' ' . $nl;


# ~   
# Step 2
# ~

# Open the log file
open(LOG, '>c:\\perl-depot\\primes\\primes.log');

# What is the upper limit?
print LOG 'Max Integer = ' . $max1 . $nl;


# ~   
# Step 3 to 9
# ~

$found1 = &StorePrimes($max1);


# ~
# Step 10
# ~

# get full time (y,m,d,  h,m,s, dy,dw,ds)
my @clock2 = System_Clock();

# calc difference (day, hr, min, sec)
my ($tday, $thr, $tmin, $tsec)= 
Delta_DHMS($clock1[0], $clock1[1], $clock1[2], $clock1[3], $clock1[4], $clock1[5],
           $clock2[0], $clock2[1], $clock2[2], $clock2[3], $clock2[4], $clock2[5]);
           
# should be in seconds
$total1 = ($tday * 86400) + ($thr * 3600) + ($tmin * 60) + $tsec;

# How many found?
print LOG 'Primes Found = ' . $found1 . $nl;
print LOG 'Elapsed Time (s) = ' . $total1 . $nl;

# Close the text file
close(LOG);



# ~
# Step 11
# ~

# Display message (crt)
print 'Ending program' . $nl;
print localtime() . $nl;
print ' ' . $nl;

print 'Elapsed Time (s) = ' . $total1 . $nl;
print ' ' . $nl;