Merge pull request #5453 from mattneleigh/pwc145

	new file:   challenge-145/mattneleigh/perl/ch-1.pl

1 files changed, 84 insertions, 0 deletions

diff --git a/challenge-145/mattneleigh/perl/ch-1.pl b/challenge-145/mattneleigh/perl/ch-1.pl
new file mode 100755
index 0000000000..c9634dfbe0
--- /dev/null
+++ b/challenge-145/mattneleigh/perl/ch-1.pl
@@ -0,0 +1,84 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use English;
+
+################################################################################
+# Begin main execution
+################################################################################
+
+my @pairs = (
+    # Given case
+    [
+        [ 1, 2, 3 ],
+        [ 4, 5, 6 ]
+    ],
+
+    # Additional test cases
+    [
+        [  1,  2,  3,  4,  5,  6,  7,  8,  9 ],
+        [ 10, 11, 12, 13, 14, 15, 16, 17, 18 ]
+    ],
+    [
+        [ 1, 2, 3, 4, 5 ],
+        [ 1, 2, 3, 4 ]
+    ]
+);
+my $pair;
+
+foreach $pair (@pairs){
+    my $dot_product = dot_product($pair->[0], $pair->[1]);
+
+    printf("\@a = (%s);\n", join(", ", @{$pair->[0]}));
+    printf("\@b = (%s);\n", join(", ", @{$pair->[1]}));
+    printf(
+        "Dot product = %s\n\n",
+        defined($dot_product) ? $dot_product : "Undefined due to error"
+    );
+}
+
+
+exit(0);
+################################################################################
+# End main execution; subroutines follow
+################################################################################
+
+
+
+################################################################################
+# Calculate the dot product of two vectors
+# Takes two arguments:
+# * A reference to an array of scalar numeric values, A
+# * A reference to an array of scalar numeric values, B
+# Returns on success:
+# * The dot product- a single scalar value- of A and B.
+# Returns on error:
+# * undef if A and B do not have the same number of members
+################################################################################
+sub dot_product{
+    my $a = shift();
+    my $b = shift();
+
+    my $i = scalar(@{$a});
+
+    # Make sure both arrays are the same
+    # length
+    return(undef)
+        unless($i == scalar(@{$b}));
+
+    my $sum = 0;
+
+    # Accumulate the sum of the products
+    # of all corresponding members of
+    # each array
+    while($i--){
+        $sum += $a->[$i] * $b->[$i];
+    }
+
+    return($sum);
+
+}
+
+
+