--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/prime	Sat Oct 29 21:40:31 2011 +0200
@@ -0,0 +1,91 @@
+#!/usr/bin/perl
+# Natalie Schlittermann BB11 Set 1
+# Primzahlzerlegung
+# Eine Zahl die in sämtlichen Primzahlen zerlegt wird
+
+use strict;
+use warnings;
+use File::Basename;
+#use Smart::Comments;
+#use diagnostics;
+
+my $ME = basename $0;
+
+#n: ist die Zahl aus der die sämtlichen Primzahlen gefiltert wird
+#i: Primzahl: diese wird durch n geteilt
+
+my $number = $ARGV[0];
+
+if (not @ARGV) {
+    # FIXME: be more verbose
+    die "$ME: Sorry, need the number\n";
+}
+
+#1. find all divisors of $number
+my @divisors = findDivisors($number);
+
+#2. delete all non primes
+
+my @primes = ();
+
+#for each element in array divisors
+foreach my $div (@divisors) { #same element in div
+
+    #find all divisors of div and save in subprimes
+    my @subprimes = findDivisors($div);
+
+    #determine length of subprimes and save in noOfDivisors
+    my $noOfDivisors = scalar(@subprimes);
+
+    #
+    if ($noOfDivisors == 0) {@primes = (@primes, $div); }
+}
+
+#print"Die Teile von $number sind: ".join(", ", @divisors)."\n";
+#print"Die Primzahlteile von $number sind: ".join(", ", @primes)."\n";
+
+my @xxx = xxx($number, @primes);
+
+if (@xxx) {
+    print join("*", @xxx), "\n"; 
+}
+else {
+    #print STDERR "Sorry, $number is prime itself!\n";
+    warn "Sorry, $number is prime itself\n!";
+}
+    
+exit;
+
+#### SUBROUTINES #####
+
+sub findDivisors {
+    my $i = 2;
+    my $m = $_[0];
+    
+    my @divisors = ();
+    
+    while ($i < $m) {
+	if($m % $i ==0){
+	    @divisors = (@divisors, $i);
+	}
+	$i++;
+    }
+    return @divisors;
+}
+
+sub xxx {
+    my $current = shift @_;
+    my @primes = @_;
+
+    my @result;
+    foreach my $prime (@primes) {
+	while (0 == ($current % $prime)) {
+	    push @result, $prime;
+	    $current = $current / $prime;
+	    # better:
+	    # $current /= $prime;
+	}
+    }
+
+    return @result;
+}