1 #!/usr/bin/perl

     2 # Natalie Schlittermann BB11 Set 1

     3 # Primzahlzerlegung

     4 # Eine Zahl die in sämtlichen Primzahlen zerlegt wird

     5 

     6 use strict;

     7 use warnings;

     8 use File::Basename;

     9 #use Smart::Comments;

    10 #use diagnostics;

    11 

    12 my $ME = basename $0;

    13 

    14 #n: ist die Zahl aus der die sämtlichen Primzahlen gefiltert wird

    15 #i: Primzahl: diese wird durch n geteilt

    16 

    17 my $number = $ARGV[0];

    18 

    19 if (not @ARGV) {

    20     # FIXME: be more verbose

    21     die "$ME: Sorry, need the number\n";

    22 }

    23 

    24 #1. find all divisors of $number

    25 my @divisors = findDivisors($number);

    26 

    27 #2. delete all non primes

    28 

    29 my @primes = ();

    30 

    31 #for each element in array divisors

    32 foreach my $div (@divisors) { #same element in div

    33 

    34     #find all divisors of div and save in subprimes

    35     my @subprimes = findDivisors($div);

    36 

    37     #determine length of subprimes and save in noOfDivisors

    38     my $noOfDivisors = scalar(@subprimes);

    39 

    40     #

    41     if ($noOfDivisors == 0) {@primes = (@primes, $div); }

    42 }

    43 

    44 #print"Die Teile von $number sind: ".join(", ", @divisors)."\n";

    45 #print"Die Primzahlteile von $number sind: ".join(", ", @primes)."\n";

    46 

    47 my @xxx = xxx($number, @primes);

    48 

    49 if (@xxx) {

    50     print join("*", @xxx), "\n"; 

    51 }

    52 else {

    53     #print STDERR "Sorry, $number is prime itself!\n";

    54     warn "Sorry, $number is prime itself\n!";

    55 }

    56     

    57 exit;

    58 

    59 #### SUBROUTINES #####

    60 

    61 sub findDivisors {

    62     my $i = 2;

    63     my $m = $_[0];

    64     

    65     my @divisors = ();

    66     

    67     while ($i < $m) {

    68 	if($m % $i ==0){

    69 	    @divisors = (@divisors, $i);

    70 	}

    71 	$i++;

    72     }

    73     return @divisors;

    74 }

    75 

    76 sub xxx {

    77     my $current = shift @_;

    78     my @primes = @_;

    79 

    80     my @result;

    81     foreach my $prime (@primes) {

    82 	while (0 == ($current % $prime)) {

    83 	    push @result, $prime;

    84 	    $current = $current / $prime;

    85 	    # better:

    86 	    # $current /= $prime;

    87 	}

    88     }

    89 

    90     return @result;

    91 }