- Added solutions by Peter Campbell Smith.

2 files changed, 105 insertions, 0 deletions

diff --git a/challenge-135/peter-campbell-smith/perl/ch-1.pl b/challenge-135/peter-campbell-smith/perl/ch-1.pl
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+++ b/challenge-135/peter-campbell-smith/perl/ch-1.pl
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+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2021-10-18
+# PWC 135 task 1
+
+use v5.20;
+use warnings;
+use strict;
+
+# You are given an integer.
+
+# Write a script find out the middle 3-digits of the given integer, if possible 
+# otherwise throw sensible error.
+
+my ($n, $length);
+
+# input
+print 'n: ';
+$n = <>;
+chomp($n);
+say qq[\nInput:  $n];
+
+# output
+print 'Output: ';
+$length = length($n);
+
+if ($n !~ m|^\d+$|) {
+	say 'not an integer';
+	
+} elsif ($length < 3) {
+	say 'too short';
+	
+} elsif (($length & 1) == 0) {
+	say 'even number of digits';
+	
+} else {   # valid number
+	say substr($n, ($length - 3) / 2, 3);
+}
diff --git a/challenge-135/peter-campbell-smith/perl/ch-2.pl b/challenge-135/peter-campbell-smith/perl/ch-2.pl
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+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2021-10-18
+# PWC 135 task 2
+
+use v5.20;
+use warnings;
+use strict;
+
+# You are given 7-characters alphanumeric SEDOL.
+
+# Write a script to validate the given SEDOL. 
+# Print 1 if it is a valid SEDOL otherwise 0.
+
+# A valid SEDOL:
+# is 7 characters long
+# has the first 6 chars matching [B-DF-HJ-NP-TV-Z0-9]
+# has a digit 0-9 as the last char
+# has a weighted sum of digits (see @weights) which is a multiple of 10
+
+my (@weights, $sedol, @tests);
+
+@weights = (1, 3, 1, 7, 3, 9, 1);   # weight of each char in the checksum (from Wikipedia)
+
+# check some known valid SEDOLs (taken from London Stock Exchange listings)
+say "\n--- VALID ---";
+@tests = qw[0263494 B7S9G98 B1VZ0M2 B12WC93 B6T5S47 BDZWB75 BLGZ986 0798059];
+for $sedol (@tests) {
+	check_sedol($sedol);
+}
+
+# check some known invalid SEDOLs
+say "\n--- INVALID ---";
+@tests = qw[BBBBBBB CCCCCC ZZZZAZ0 BCDFGH* BDZWB76 1798059];
+for $sedol (@tests) {
+	check_sedol($sedol);
+}
+
+sub check_sedol {
+	
+	my ($SEDOL, $check_sum, $j, $char, $char_value);
+
+	$SEDOL = $_[0];
+	say qq[\nInput:  \$SEDOL = $SEDOL];
+
+	# check length and valid chars
+	unless ($SEDOL =~ m|^[B-DF-HJ-NP-TV-Z0-9]{6}\d$|) {
+		say qq[Output: 0 (wrong length or invalid chars)];
+		return;
+	}
+	
+	# calculate checksum
+	@weights = (1, 3, 1, 7, 3, 9, 1);
+	$check_sum = 0;
+	for $j (0..6) {
+		$char = substr($SEDOL, $j, 1);
+		$char_value = ord($char) - ($char =~ m|\d| ? ord('0') : ord('A') - 10);
+		$check_sum += $weights[$j] * $char_value;
+	}
+
+	# is it a multiple of 10?
+	if ($check_sum % 10 == 0) {
+		say 'Output: 1';
+	} else {
+		say qq[Output: 0 (checksum is $check_sum - not a multiple of 10)];
+	}
+}