2016 Update

Task/Order-two-numerical-lists/Perl/order-two-numerical-lists.pl

@@ -1,36 +1,38 @@
-#!/usr/bin/perl -w
-use strict ;
+use strict;
+use warnings;
 
 sub orderlists {
-   my $firstlist = shift ;
-   my $secondlist = shift ;
-   my $first = shift @{$firstlist } if @{$firstlist} ;
-   my $second ;
-#keep stripping elements from the first list as long as there are any
-#or until the second list is used up!
-   while ( @{$firstlist} ) {
-      if ( @{$secondlist} ) { #second list is not used up yet!
-	 $second = shift @{$secondlist} ;
-	 if ( $first < $second ) {
-	    return 1 ;
-	 }
-	 if ( $first > $second ) {
-	    return 0 ;
-	 }
-      }
-      else {                  #second list used up, defined to return false
-	 return 0 ;
-      }
-      $first = shift @{$firstlist} ;
-   }
-   return 0 ;                 #in all remaining cases return false
+    my ($firstlist, $secondlist) = @_;
+
+    my ($first, $second);
+    while (@{$firstlist}) {
+        $first = shift @{$firstlist};
+        if (@{$secondlist}) {
+            $second = shift @{$secondlist};
+            if ($first < $second) {
+                return 1;
+            }
+            if ($first > $second) {
+                return 0;
+            }
+        }
+        else {
+            return 0;
+        }
+    }
+
+    @{$secondlist} ? 1 : 0;
 }
 
-my @firstnumbers = ( 43 , 33 , 2  ) ;
-my @secondnumbers = ( 45 ) ;
-if ( orderlists( \@firstnumbers , \@secondnumbers ) ) {
-   print "The first list comes before the second list!\n" ;
-}
-else {
-   print "The first list does not come before the second list!\n" ;
+foreach my $pair (
+    [[1, 2, 4], [1, 2, 4]],
+    [[1, 2, 4], [1, 2,  ]],
+    [[1, 2,  ], [1, 2, 4]],
+    [[55,53,1], [55,62,83]],
+    [[20,40,51],[20,17,78,34]],
+) {
+    my $first  = $pair->[0];
+    my $second = $pair->[1];
+    my $before = orderlists([@$first], [@$second]) ? 'true' : 'false';
+    print "(@$first) comes before (@$second) : $before\n";
 }