#!/usr/bin/perl

# # # # # # # # # # # #
# # # # # # # bullshit


for ($i = 0; $i < 80; $i++)
    {
    print "\n";
    }


print "mersenne tester\n";
print "\n";
print "\n";
print "format: 2^p-1\n";
print "if 2^p-1 is prime, it is a mersenne prime\n";

# # # # # # # # # # # # # #
# # # # # # get information

$p = 0;
$number = 0;
$half = 0;
$count = 0;
$divisor = 0;

$count_two = 0;

$divisor = 2;


# # # # # # # # # # # # #
# # # # # # begin testing

print "enter p:\n";
$p = <STDIN>;

$number = (2 ** $p) -1;

print "you entered ", $p, " 2^p is ", ($number + 1), " and number \= $number\n";

$half = $number / 2;

print "testing\n";

$count_two = 1;

print "\n\n";

for ($count=1; $count<$half; ++$count)
    {
    ++$count_two;
    if($number % $divisor == 0)
        {
        print "2^", $p, "-1 is not a mersenne prime.\n";    # # # # # # # # # # # #
        print "it took $count_two passes to complete,\n";   # # # # # # # # too bad
        print "and was divided by ", $divisor, ".\n";
        exit(0);
        }
        else
        {
            if($number % $divisor > 0)
            {
            ++$divisor;

            print "pass # $count\n";
            }
        }
    }

# # # # # # # # # # # #
# # # # # # # # success

print "\n";
print "2^", $p, "-1 is a mersenne prime.\n";
print "it took $count_two passes to complete.\n";

$char_quit = <STDIN>;