new files

Task/Bulls-and-cows/Perl/bulls-and-cows.pl

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+use Data::Random qw(rand_set);
+use List::MoreUtils qw(uniq);
+
+my $size = 4;
+my $chosen = join "", rand_set set => ["1".."9"], size => $size;
+
+print "I've chosen a number from $size unique digits from 1 to 9; you need
+to input $size unique digits to guess my number\n";
+
+for ( my $guesses = 1; ; $guesses++ ) {
+    my $guess;
+    while (1) {
+        print "\nNext guess [$guesses]: ";
+        $guess = <STDIN>;
+        chomp $guess;
+        checkguess($guess) and last;
+        print "$size digits, no repetition, no 0... retry\n";
+    }
+    if ( $guess eq $chosen ) {
+        print "You did it in $guesses attempts!\n";
+        last;
+    }
+    my $bulls = 0;
+    my $cows = 0;
+    for my $i (0 .. $size-1) {
+        if ( substr($guess, $i, 1) eq substr($chosen, $i, 1) ) {
+            $bulls++;
+        } elsif ( index($chosen, substr($guess, $i, 1)) >= 0 ) {
+            $cows++;
+        }
+    }
+    print "$cows cows, $bulls bulls\n";
+}
+
+sub checkguess
+{
+    my $g = shift;
+    return uniq(split //, $g) == $size && $g =~ /^[1-9]{$size}$/;
+}