#include <iostream>
#include <random>

using namespace std;

int count_correct(string& secret, string const& guess)
{
  int count = 0;
  for (unsigned int i = 0; i < secret.size(); ++i)
  {
    if (secret.at(i) == guess.at(i))
    {
      secret.at(i) = ' '; // do not count again!
      ++count;
    }
  }
  return count;
}

int count_existing(string& secret, string const& guess)
{
  int count = 0;
  for (unsigned int i = 0; i < guess.size(); ++i)
  {
    unsigned int pos = secret.find( guess.at(i) );

    if ( pos != string::npos )
    {
      secret.at(pos) = ' '; // do not count again!
      ++count;
    }
  }
  return count;
}

int main()
{
  random_device rdev;
  uniform_int_distribution<int> dist(1000, 9999);

  const string secret = to_string(dist(rdev));
  string guess;
  int round = 0;

  cout << secret << endl;
  cout << "A secret number is generated, enter your guesses: " << endl;
  
  do
  {
    ++round;
    cin >> guess;
    cin.ignore(1000, '\n');

    if (guess.size() != 4)
    {
      cerr << "     ERROR: Your guess should be 4 digits!" << endl;
    }
    else
    {
      string scopy = secret;
      int correct = count_correct(scopy, guess);
      int wrong_place = count_existing(scopy, guess);
      cout << "     "
           << correct << " correct and "
           << wrong_place << " in wrong place!"
           << endl;
    }
  }
  while (guess != secret);

  cout << "Correct! You won in " << round << " rounds!" << endl;

  return 0;
}