Bulls and cows/Player: Difference between revisions

=={{header|C sharp|C#}}==

{{works with|C#|3.0}}

<lang csharp>

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace BullsAndCows

{

class Program

{

const int ANSWER_SIZE = 4;

static IEnumerable<string> Permutations(int size)

{

if (size > 0)

{

foreach (string s in Permutations(size - 1))

foreach (char n in "123456789")

if (!s.Contains(n))

yield return s + n;

}

else

yield return "";

}

static IEnumerable<T> Shuffle<T>(IEnumerable<T> source)

{

Random random = new Random();

List<T> list = source.ToList();

while (list.Count > 0)

{

int ix = random.Next(list.Count);

yield return list[ix];

list.RemoveAt(ix);

}

}

static bool ReadBullsCows(out int bulls, out int cows)

{

string[] input = Console.ReadLine().Split(',').ToArray();

bulls = cows = 0;

if (input.Length < 2)

return false;

else

return int.TryParse(input[0], out bulls)

&& int.TryParse(input[1], out cows);

}

static void Main(string[] args)

{

Console.WriteLine("Bulls and Cows");

Console.WriteLine("==============");

Console.WriteLine();

List<string> answers = Shuffle(Permutations(ANSWER_SIZE)).ToList();

while (answers.Count > 1)

{

string guess = answers[0];

Console.Write("My guess is {0}. How many bulls, cows? ", guess);

int bulls, cows;

if (!ReadBullsCows(out bulls, out cows))

Console.WriteLine("Sorry, I didn't understand that. Please try again.");

else

for (int ans = answers.Count - 1; ans >= 0; ans--)

{

int tb = 0, tc = 0;

for (int ix = 0; ix < ANSWER_SIZE; ix++)

if (answers[ans][ix] == guess[ix])

tb++;

else if (answers[ans].Contains(guess[ix]))

tc++;

if ((tb != bulls) || (tc != cows))

answers.RemoveAt(ans);

}

}

if (answers.Count == 1)

Console.WriteLine("Hooray! The answer is {0}!", answers[0]);

else

Console.WriteLine("No possible answer fits the scores you gave.");

}

}

}

</lang>

Example output:-

<pre>

Bulls and Cows

==============

My guess is 7854. How many bulls, cows? 0,1

My guess is 1539. How many bulls, cows? 1,2

My guess is 2935. How many bulls, cows? 2,1

My guess is 9635. How many bulls, cows? 1,3

Hooray! The answer is 5936!

</pre>

=={{header|Raku}}==

(formerly Perl 6)

{{works with|Rakudo|2018.12}}

{{trans|Perl}}

<lang perl6># we use the [] reduction meta operator along with the Cartesian Product

# operator X to create the Cartesian Product of four times [1..9] and then get

# all the elements where the number of unique digits is four.

my @candidates = ([X] [1..9] xx 4).grep: *.unique == 4;

repeat {

my $guess = @candidates.pick;

my ($bulls, $cows) = read-score;

@candidates .= grep: &score-correct;

# note how we declare our two subroutines within the repeat block. This

# limits the scope in which the routines are known to the scope in which

# they are needed and saves us a lot of arguments to our two routines.

sub score-correct($a) {

my $exact = [+] $a >>==<< $guess;

# number of elements of $a that match any element of $b

my $loose = +$a.grep: any @$guess;

return $bulls == $exact && $cows == $loose - $exact;

}

sub read-score() {

loop {

my $score = prompt "My guess: {$guess.join}.\n";

if $score ~~ m:s/^ $<bulls>=(\d) $<cows>=(\d) $/

and $<bulls> + $<cows> <= 4 {

return +$<bulls>, +$<cows>;

}

say "Please specify the number of bulls and cows";

}

}

} while @candidates > 1;

say @candidates

?? "Your secret number is {@candidates[0].join}!"

!! "I think you made a mistake with your scoring.";</lang>

{{out}}

<pre>My guess: 4235.

2 1

My guess: 1435.

2 1

My guess: 1245.

2 1

Your secret number is 1234!</pre>