imported my solutions to challenge 31

3 files changed, 65 insertions, 9 deletions

diff --git a/challenge-031/duncan-c-white/README b/challenge-031/duncan-c-white/README
index 2d973d0053..5e1aee6697 100644
--- a/challenge-031/duncan-c-white/README
+++ b/challenge-031/duncan-c-white/README
@@ -1,13 +1,11 @@
-Challenge 1: "Write a script to list dates for Sunday Christmas between
-	      2019 and 2100. For example, 25 Dec 2022 is Sunday."
+Challenge 1: "Create a function to check divide by zero error without
+	      checking if the denominator is zero."
 
-My notes: Very well defined, another job for Date::Manip or Date::Simple..
+My notes: so eval then?
 
 
-Challenge 2: "Write a script to print all possible series of 3 positive
-	      numbers, where in each series at least one of the number is even and
-	      sum of the three numbers is always 12. For example, 3,4,5."
+Challenge 2: "Create a script to demonstrate creating dynamic variable
+	      name, assign a value to the variable and finally print the
+	      variable. The variable name is passed as a command line argument."
 
-My notes: Well defined, looks straightforward by brute forcish search (with
-the third number in the sequence being fixed as 12-first-second of course,
-so only two degrees of freedom).
+My notes: so eval again?
diff --git a/challenge-031/duncan-c-white/perl5/ch-1.pl b/challenge-031/duncan-c-white/perl5/ch-1.pl
new file mode 100755
index 0000000000..5a55e655c2
--- /dev/null
+++ b/challenge-031/duncan-c-white/perl5/ch-1.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/perl
+#
+# Challenge 1: "Create a function to check divide by zero error without
+#	      checking if the denominator is zero."
+#
+# My notes: so eval then?
+# 
+
+use v5.10;	# to get "say"
+use strict;
+use warnings;
+
+die "Usage: ch-1.pl a b\n" unless @ARGV==2;
+my $a = shift;
+my $b = shift;
+
+my $x;
+if( defined eval { $x = $a / $b } )
+{
+	say "$a / $b = $x";
+} else
+{
+	say "error: $@";
+}
diff --git a/challenge-031/duncan-c-white/perl5/ch-2.pl b/challenge-031/duncan-c-white/perl5/ch-2.pl
new file mode 100755
index 0000000000..3a00f4e73b
--- /dev/null
+++ b/challenge-031/duncan-c-white/perl5/ch-2.pl
@@ -0,0 +1,34 @@
+#!/usr/bin/perl
+#
+# Challenge 2: "Create a script to demonstrate creating dynamic variable
+# 	      name, assign a value to the variable and finally print the
+# 	      variable. The variable name is passed as a command line argument."
+# 
+# My notes: so eval again? let's take a list of variable names,
+# 	    and increment each variable each time..
+#
+
+use v5.10;	# for "say"
+use strict;
+use warnings;
+use Data::Dumper;
+
+die "Usage: ch-2.pl [x|y]+\n" if @ARGV==0;
+my @bad = grep { ! "x" && ! "y" } @ARGV;
+
+die "ch-2.pl: bad variables @bad, not x or y\n" unless @bad==0;
+
+my $x=0;
+my $y=0;
+
+foreach my $v (@ARGV)
+{
+	my $var = '$'.$v;
+	#say "debug: var=$var";
+
+	my $str = $var.'++';
+	#say "debug: str=$str";
+	eval $str;
+}
+
+say "x=$x, y=$y";