Task: Bulls and cows_Player

C: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

char *list;
const char *line = "--------+--------------------\n";
int len = 0;

int irand(int n)
{
	int r, rand_max = RAND_MAX - (RAND_MAX % n);
	do { r = rand(); } while(r >= rand_max);
	return r / (rand_max / n);
}

char* get_digits(int n, char *ret)
{
	int i, j;
	char d[] = "123456789";

	for (i = 0; i < n; i++) { 
		j = irand(9 - i);
		ret[i] = d[i + j];
		if (j) d[i + j] = d[i], d[i] = ret[i];
	}
	return ret;
}

#define MASK(x) (1 << (x - '1'))
int score(const char *digits, const char *guess, int *cow)
{
	int i, bits = 0, bull = *cow = 0;

	for (i = 0; guess[i] != '\0'; i++)
		if (guess[i] != digits[i])
			bits |= MASK(digits[i]);
		else ++bull;

	while (i--) *cow += ((bits & MASK(guess[i])) != 0);

	return bull;
}

void pick(int n, int got, int marker, char *buf)
{
	int i, bits = 1;
	if (got >= n)
		strcpy(list + (n + 1) * len++, buf);
	else
		for (i = 0; i < 9; i++, bits *= 2) {
			if ((marker & bits)) continue;
			buf[got] = i + '1';
			pick(n, got + 1, marker | bits, buf);
		}
}

void filter(const char *buf, int n, int bull, int cow)
{
	int i = 0, c;
	char *ptr = list;

	while (i < len) {
		if (score(ptr, buf, &c) != bull || c != cow)
			strcpy(ptr, list + --len * (n + 1));
		else
			ptr += n + 1, i++;
	}
}

void game(const char *tgt, char *buf)
{
	int i, p, bull, cow, n = strlen(tgt);

	for (i = 0, p = 1; i < n && (p *= 9 - i); i++);
	list = malloc(p * (n + 1));

	pick(n, 0, 0, buf);
	for (p = 1, bull = 0; n - bull; p++) {
		strcpy(buf, list + (n + 1) * irand(len));
		bull = score(tgt, buf, &cow);

		printf("Guess %2d| %s    (from: %d)\n"
			"Score   | %d bull, %d cow\n%s",
			p, buf, len, bull, cow, line);

		filter(buf, n, bull, cow);
	}
}

int main(int c, char **v)
{
	int n = c > 1 ? atoi(v[1]) : 4;

	char secret[10] = "", answer[10] = "";
	srand(time(0));

	printf("%sSecret  | %s\n%s", line, get_digits(n, secret), line);
	game(secret, answer);

	return 0;
}











Ada: with Ada.Text_IO;
with Ada.Containers.Vectors;
with Ada.Numerics.Discrete_Random;

procedure Bulls_Player is

   
   package Nat_IO is new Ada.Text_IO.Integer_IO (Natural);

   
   use type Ada.Containers.Count_Type;

   
   Guessing_Length : constant := 4;

   
   type Digit is range 1 .. 9;
   
   type Sequence is array (1 .. Guessing_Length) of Digit;

   
   package Sequence_Vectors is new Ada.Containers.Vectors
     (Element_Type => Sequence,
      Index_Type   => Positive);

   
   function Is_Valid (S : Sequence) return Boolean is
      Appeared : array (Digit) of Boolean := (others => False);
   begin
      for I in S'Range loop
         if Appeared (S (I)) then
            return False;
         end if;
         Appeared (S (I))  := True;
      end loop;
      return True;
   end Is_Valid;

   
   procedure Fill_Pool (Pool : in out Sequence_Vectors.Vector) is
      Finished : exception;
      
      function Next (S : Sequence) return Sequence is
         Result : Sequence := S;
         Index  : Positive := S'Last;
      begin
         loop
         
            if Result (Index) = Digit'Last then
               Result (Index) := Digit'First;
               
               
               if Index = Result'First then
                  raise Finished;
               end if;
               Index := Index - 1;
            else
               Result (Index) := Result (Index) + 1;
               return Result;
            end if;
         end loop;
      end Next;
      X        : Sequence := (others => 1);
   begin
      loop
      
         if Is_Valid (X) then
            Pool.Append (X);
         end if;
         X := Next (X);
      end loop;
   exception
      when Finished =>
         
         
         null;
   end Fill_Pool;

   
   function Random_Index (Pool : Sequence_Vectors.Vector) return Positive is
      subtype Possible_Indexes is Positive range
        Pool.First_Index .. Pool.Last_Index;
      package Index_Random is new Ada.Numerics.Discrete_Random
        (Possible_Indexes);
      Index_Gen : Index_Random.Generator;
   begin
      Index_Random.Reset (Index_Gen);
      return Index_Random.Random (Index_Gen);
   end Random_Index;

   
   procedure Get_Answer (S : Sequence; Bulls, Cows : out Natural) is
      Valid : Boolean := False;
   begin
      Bulls := 0;
      Cows  := 0;
      while not Valid loop
         
         Ada.Text_IO.Put ("How is the score for:");
         for I in S'Range loop
            Ada.Text_IO.Put (Digit'Image (S (I)));
         end loop;
         Ada.Text_IO.New_Line;
         begin
            Ada.Text_IO.Put ("Bulls:");
            Nat_IO.Get (Bulls);
            Ada.Text_IO.Put ("Cows:");
            Nat_IO.Get (Cows);
            if Bulls + Cows <= Guessing_Length then
               Valid := True;
            else
               Ada.Text_IO.Put_Line ("Invalid answer, try again.");
            end if;
         exception
            when others =>
               null;
         end;
      end loop;
   end Get_Answer;

   
   procedure Strip
     (V           : in out Sequence_Vectors.Vector;
      S           : Sequence;
      Bulls, Cows : Natural)
   is
      function Has_To_Be_Removed (Position : Positive) return Boolean is
         Testant    : constant Sequence := V.Element (Position);
         Bull_Score : Natural           := 0;
         Cows_Score : Natural := 0;
      begin
         for I in Testant'Range loop
            for J in S'Range loop
               if Testant (I) = S (J) then
                  
                  if I = J then
                     Bull_Score := Bull_Score + 1;
                  else
                     Cow_Score := Cow_Score + 1;
                  end if;
               end if;
            end loop;
         end loop;
         return Cow_Score /= Cows or else Bull_Score /= Bulls;
      end Has_To_Be_Removed;
   begin
      for Index in reverse V.First_Index .. V.Last_Index loop
         if Has_To_Be_Removed (Index) then
            V.Delete (Index);
         end if;
      end loop;
   end Strip;

   
   procedure Solve is
      All_Sequences : Sequence_Vectors.Vector;
      Test_Index    : Positive;
      Test_Sequence : Sequence;
      Bulls, Cows   : Natural;
   begin
      
      Fill_Pool (All_Sequences);
      loop
      
         Test_Index    := Random_Index (All_Sequences);
         Test_Sequence := All_Sequences.Element (Test_Index);
         
         Get_Answer (Test_Sequence, Bulls, Cows);
         
         exit when Bulls = 4;
         All_Sequences.Delete (Test_Index);
         Strip (All_Sequences, Test_Sequence, Bulls, Cows);
         exit when All_Sequences.Length <= 1;
      end loop;
      if All_Sequences.Length = 0 then
         
         Ada.Text_IO.Put_Line
           ("I give up, there has to be a bug in" &
            "your scoring or in my algorithm.");
      else
         if All_Sequences.Length = 1 then
            Ada.Text_IO.Put ("The sequence you thought has to be:");
            Test_Sequence := All_Sequences.First_Element;
         else
            Ada.Text_IO.Put ("The sequence you thought of was:");
         end if;
         for I in Test_Sequence'Range loop
            Ada.Text_IO.Put (Digit'Image (Test_Sequence (I)));
         end loop;
      end if;
   end Solve;

begin
   
   Ada.Text_IO.Put_Line ("Bulls and Cows, Your turn!");
   Ada.Text_IO.New_Line;
   Ada.Text_IO.Put_Line
     ("Think of a sequence of" &
      Integer'Image (Guessing_Length) &
      " different digits.");
   Ada.Text_IO.Put_Line ("I will try to guess it. For each correctly placed");
   Ada.Text_IO.Put_Line ("digit I score 1 Bull. For each digit that is on");
   Ada.Text_IO.Put_Line ("the wrong place I score 1 Cow. After each guess");
   Ada.Text_IO.Put_Line ("you tell me my score.");
   Ada.Text_IO.New_Line;
   Ada.Text_IO.Put_Line ("Let's start.");
   Ada.Text_IO.New_Line;
   
   Solve;
end Bulls_Player;