Merge pull request #1243 from jacoby/master

The fun part is counting up from 100

3 files changed, 126 insertions, 0 deletions

diff --git a/challenge-047/dave-jacoby/blog.txt b/challenge-047/dave-jacoby/blog.txt
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--- /dev/null
+++ b/challenge-047/dave-jacoby/blog.txt
@@ -0,0 +1 @@
+https://jacoby.github.io/2020/02/12/counting-from-100-is-the-fun-part.html
\ No newline at end of file
diff --git a/challenge-047/dave-jacoby/perl/ch-1.pl b/challenge-047/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..bb0d151256
--- /dev/null
+++ b/challenge-047/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,32 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use utf8;
+use feature qw{ postderef say signatures state switch };
+no warnings
+  qw{ experimental::postderef experimental::smartmatch experimental::signatures };
+
+use Roman;
+
+my %operators = map { $_ => 1 } qw{ + - / * };
+
+if ( scalar @ARGV > 2 ) {
+    my ( $r1, $op, $r2 ) = @ARGV;
+    if ( !$operators{$op} ) {
+        say 'not an operator';
+        exit;
+    }
+    if ( !isroman($r1) ) { say qq{"$r1" is not a roman numeral}; exit; }
+    if ( !isroman($r2) ) { say qq{"$r2" is not a roman numeral}; exit; }
+    my $a1 = arabic($r1);
+    my $a2 = arabic($r2);
+    my $a3 = 0;
+    if ( $op eq '+' ) { $a3 =  $a1 + $a2 }
+    if ( $op eq '-' ) { $a3 =  $a1 - $a2 }
+    if ( $op eq '*' ) { $a3 =  $a1 * $a2 }
+    if ( $op eq '/' ) { $a3 =  $a1 / $a2 }
+    my $r3 = uc roman($a3);
+    say qq{ $r1 $op $r2 = $r3 };
+}
+else { say 'We need an operator and two roman numbers' }
diff --git a/challenge-047/dave-jacoby/perl/ch-2.pl b/challenge-047/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..1e3904653f
--- /dev/null
+++ b/challenge-047/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,93 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use utf8;
+use feature qw{ postderef say signatures state switch };
+no warnings qw{ experimental::postderef experimental::smartmatch experimental::signatures };
+
+# Write a script to print first 20 Gapful Numbers
+# greater than or equal to 100.
+
+# a Gapful Number is a number where
+#   a second number is formed by the first and last digit of the number
+#   which is a factor in that number.
+# for example, 100 forms 10 and 100/10 = 10
+# while 101 forms 11 and 101/11 = 9.181818...
+
+# When I'm trying to be readable,
+#   I declare an array to push things into
+#   I use a while loop based on the size of that array
+#   I iterate through numbers with ++
+#   I split the number into an array with the easiest regex
+#     and I join with an empty string
+#   I push to the array if $n % $i == 0
+
+my @x;
+my $n = 100;
+while ( scalar @x < 20 ) {
+	my @n = split //, $n;
+	my $i = join '', $n[0], $n[-1];
+	push @x, $n if $n % $i == 0;
+	$n++;
+}
+say join "\n", @x;
+
+say '-' x 30;
+
+# When I'm trying to show off a little more
+#   I use a for loop ending at an abstractly large point
+#   I name the for loop
+#   I use state so the count variable only exists within the loop
+#   I use the named last to break the loop
+
+LOOP: for my $n ( 100 .. 1000 ) {
+	state $c = 0;
+	my @n = split //, $n;
+	my $i = join '', $n[0], $n[-1];
+	if ( 0 == $n % $i ) {
+		$c++;
+		say $n;
+	}
+	last LOOP if $c >= 20;
+}
+
+say '-' x 30;
+
+# When I'm trying to be way-cool functional dev
+#   I start with a range of 100..1000
+#   I use join to stringify the output
+#   I use a grep and a state variable to limit to 20
+#   I use substr to pull the first and last digit from the number
+#     and only create one variable in the second grep
+
+say join "\n", grep { state $c = 0; $c++ < 20 }
+	grep { my $i = join '', substr( $_, 0, 1 ), substr( $_, -1 ); $_ % $i == 0 }100 .. 1000;
+
+say '-' x 30;
+
+my $next = make_iterator(100);
+
+while ( my $n = $next->() ) {
+	state $c = 0;
+	my $i =  my $i = join '', substr( $n, 0, 1 ), substr( $n, -1 );
+	if ( 0==$n%$i){
+		say $n;
+		$c++;
+	}
+	last if $c >19;
+}
+
+sub make_iterator ( $start ) {
+	return sub {
+		state $i = $start;
+		return $i++;
+		}
+}
+
+# the right answers:
+# 100, 105, 108, 110, 120,
+# 121, 130, 132, 135, 140,
+# 143, 150, 154, 160, 165,
+# 170, 176, 180, 187, 190
+