- Added solutions by Burkhard Nickels.

4 files changed, 261 insertions, 0 deletions

diff --git a/challenge-031/burkhard-nickels/perl5/Div.pm b/challenge-031/burkhard-nickels/perl5/Div.pm
new file mode 100644
index 0000000000..f7215fc8d6
--- /dev/null
+++ b/challenge-031/burkhard-nickels/perl5/Div.pm
@@ -0,0 +1,126 @@
+#!/usr/bin/perl
+
+package Div;
+
+use strict;
+use warnings;
+use Data::Dumper qw(Dumper);
+require Exporter;
+
+=head1 NAME
+
+Div - Division by Zero Test
+
+=head1 SYNOPSIS
+
+ use Div qw(debug);
+ my $DEBUG=0;
+
+ my $a = Div->new(4);
+ my $b = 2; 
+  or 
+ my $b = 0;
+ my $r = $a/$b;
+ print "Division $a/$b = $r\n";
+ debug($a,$b,$r) if $DEBUG;
+
+=head1 DESCRIPTION
+
+This is Task#01 of Perl Weekly Challenge #31 / 2019. A division by Zero shall
+be recognized without evaluating the divisor for zero value. Here it is done
+with traping the exception in an C<eval> block. The result (scalar ref) is
+blessed.
+
+	eval { $res = $$self / $divisor };
+	if($@ =~ /division by zero/) { $ret = "Division by zero is not allowed!"; }
+	else { $ret = ref $res ? $res : bless \$res; }
+
+Additionally a class for the division C<Div> is defined and the "/" operator 
+is overloaded. A static debug function can be imported, that shows  the
+blessing of a scalar ref. 
+
+ use overload 
+	'/' => \&divide,
+	'""' => \&out,
+	'fallback' => 1;
+
+=cut
+
+use overload 
+	'/' => \&divide,
+	'""' => \&out,
+	'fallback' => 1;
+
+our @ISA = qw(Exporter);
+our @EXPORT_OK = qw(debug);
+$Data::Dumper::Indent=0;
+
+=head2 new() - Constructor
+
+Creates a number as Dividend.
+
+ my $a = Div->new(4);
+
+=cut
+
+sub new {
+	my ($class,$n) = @_;
+	my $self = \$n;
+	bless $self, $class;
+}
+
+=head2 divide() - division
+
+Divides the object with a number.
+
+ my $result = $a->divide(2);
+  or
+ my $result = $a / 2;
+
+=cut
+
+sub divide {
+	my ($self,$divisor) = @_;
+	my ($ret,$res);
+	eval { $res = $$self / $divisor };
+	if($@ =~ /division by zero/) { $ret = "Division by zero is not allowed!"; }
+	else { $ret = ref $res ? $res : bless \$res; }
+	return $ret;
+}
+
+=head2 out() - output
+
+Output of the object. This methode needs to be defined and the '""' needs to
+be overloaded with this function.
+
+Otherwise the output of the number in a print function would not work.
+
+ print "Dividend: $a"
+
+=cut
+
+sub out { my $self = shift; return $$self; }
+
+=head2 debug() - debugging of blessed scalar ref
+
+This is a static function to show the blessing of a scalar reference.
+Because it is outside the object I did an Export on it, that it can be
+used without Class name.
+
+=cut
+
+sub debug {
+	my (@v) = @_;
+	for(my $i=0; $i<=$#v; $i++) { 
+		my $w = $v[$i];
+		printf("Value %02d: %-10s (%2s) %s\n",$i,ref($w),$w,Dumper($w));
+	}
+}
+
+=head1 AUTHOR
+
+Chuck
+
+=cut
+
+1;
diff --git a/challenge-031/burkhard-nickels/perl5/ch-1.pl b/challenge-031/burkhard-nickels/perl5/ch-1.pl
new file mode 100644
index 0000000000..216e46d34b
--- /dev/null
+++ b/challenge-031/burkhard-nickels/perl5/ch-1.pl
@@ -0,0 +1,35 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+my ($r,$a,$b);
+
+# Division with function divide
+# ------------------------------
+($a,$b) = (5,2);
+$r = divide($a,$b);
+print "Division $a/$b = $r\n";
+
+# Catches the execption and returns message.
+# ------------------------------
+($a,$b) = (4,0);
+$r = divide($a,$b);
+print "Division $a/$b = $r\n";
+
+# Throws an exception
+# ------------------------------
+($a,$b) = (4,0);
+$r = $a/$b;
+print "Division $a/$b = $r\n";
+
+# ------------------- Divide Function ---------------------
+sub divide {
+	my ($dividend,$divisor) = @_;
+	my $result;
+	eval { $result = $dividend/$divisor; };
+	if($@ =~ /division by zero/) { $result = "Division by zero is not allowed!"; }
+	return $result;
+}
+
+
diff --git a/challenge-031/burkhard-nickels/perl5/ch-1a.pl b/challenge-031/burkhard-nickels/perl5/ch-1a.pl
new file mode 100644
index 0000000000..5ad647a8a5
--- /dev/null
+++ b/challenge-031/burkhard-nickels/perl5/ch-1a.pl
@@ -0,0 +1,40 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use lib '.';
+use Div qw(debug);
+my $DEBUG=0;
+
+{
+my $a = Div->new(4);
+my $b = 2;
+my $r = $a/$b;
+print "Division $a/$b = $r\n";
+debug($a,$b,$r) if $DEBUG;
+}
+
+{
+my $a = Div->new(4);
+my $b = 0;
+my $r = $a/$b;
+print "Division $a/$b = $r\n";
+debug($a,$b,$r) if $DEBUG;
+}
+
+{
+my $a = Div->new(5);
+my $b = 3;
+my $r = $a/$b;
+print "Division $a/$b = $r\n";
+debug($a,$b,$r) if $DEBUG;
+}
+
+{
+my $a = Div->new(8);
+my $b = 0;
+my $r = $a/$b;
+print "Division $a/$b = $r\n";
+debug($a,$b,$r) if $DEBUG;
+}
+
diff --git a/challenge-031/burkhard-nickels/perl5/ch-2.pl b/challenge-031/burkhard-nickels/perl5/ch-2.pl
new file mode 100644
index 0000000000..d23651c608
--- /dev/null
+++ b/challenge-031/burkhard-nickels/perl5/ch-2.pl
@@ -0,0 +1,60 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use lib '.';
+use Getopt::Long;
+use Div qw(debug);
+my $DEBUG=0;
+
+my ($list,$dividend,$divisor) = (0,"","");
+my $o = GetOptions ("list" => \$list, "dividend=s" => \$dividend, "divisor=s" => \$divisor);
+if(!$o) { usage(); die("Error in command line arguments\n"); }
+
+my %vars = (
+	var4 => 4,
+	var2 => 2,
+	var1 => 1,
+	zero => 0,
+	pi   => 3.1417,
+	eternal => 9999.9999,
+);
+
+if($list) { list(); }
+elsif($dividend and $divisor and 
+	($vars{$dividend} or $dividend eq "zero") and 
+	($vars{$divisor}  or $divisor eq "zero")) { 
+		compute($vars{$dividend},$vars{$divisor}); 
+}
+else { 
+	usage(); 
+}
+
+# ----------------- Functions ----------------
+sub list {
+	print "List of Vars:\n";
+	foreach my $k (keys %vars) {
+		printf("   %-8s: %5.5f\n", $k, $vars{$k});
+	}
+}
+sub usage {
+	print "Usage: ./pwc312.pl [--list|-l] [--dividend <nr> --divisor <nr>]\n";
+	print "   Script is dividing two numbers, dividend/divisor.\n";
+	print "   --list,     list of possible variables.\n";
+	print "   --dividend, dividend for division.\n";
+	print "   --divisor,  divisor for division.\n";
+	print "   Examples:\n";
+	print "   ./pwc312.pl -l\n";
+	print "   ./pwc312.pl --dividend var1 --divisor var2\n";
+	print "   ./pwc312.pl --dividend=var1 --divisor=var3\n";
+}
+
+sub compute {
+	my ($dividend,$divisor) = @_;
+	my $a = Div->new($dividend);
+	my $b = $divisor;
+	my $r = $a/$b;
+	print "Division $a/$b = $r\n";
+	debug($a,$b,$r) if $DEBUG;
+}
+