Solution to task 1

1 files changed, 64 insertions, 0 deletions

diff --git a/challenge-142/jo-37/perl/ch-1.pl b/challenge-142/jo-37/perl/ch-1.pl
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+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use Math::Prime::Util 'divisors';
+use experimental 'signatures';
+
+our ($tests, $examples, $base);
+$base //= 10;
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV == 2;
+usage: $0 [-examples] [-tests] [-base=B] [M N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-base=B
+    Use base B. Default: 10
+
+M N
+    count the divisors of M having N as last digit in base B.
+
+EOS
+
+
+### Input and Output
+
+say num_div_mod(@ARGV, $base);
+
+
+### Implementation
+
+# Generalizing the task by taking "the last digit" in a given base.
+sub num_div_mod ($m, $n, $base=10) {
+    scalar grep $_ % $base == $n, divisors $m
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is num_div_mod(24, 2), 2, 'example 1';
+        is num_div_mod(30, 5), 2, 'example 2';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is num_div_mod(9, 1, 2), 3, 'odd divisors of 9';
+        is num_div_mod(8, 0, 2), 3, 'even divisors of 8';
+        is num_div_mod(24, 0, 1), 8, 'all divisors of 24';
+	}
+
+    done_testing;
+    exit;
+}