int numberArray[13];
constexpr int N {sizeof(numberArray) / sizeof(numberArray[0])};

long randomDealt;

void setup()
{
  Serial.begin(115200);

  pinMode(3, INPUT_PULLUP);

  randomSeed(0xbadc0de);
}

void loop()
{
  for (int ii = 0; ii < N; ii++)
    numberArray[ii] = -1;

  deal4();
  
  Serial.println("");

  for (int ii = 0; ii < N; ii++) {
    Serial.print(numberArray[ii]);
    Serial.print(" ");
  }
  
  Serial.println("");
  Serial.println("");

  delay(300);
  while (digitalRead(3) == HIGH);
}

// Fisher Yates initialise and shuffle. oh, Knuth.
void deal2()
{
  for (unsigned char tt = 0; tt < N; tt++) {
    unsigned char card = random(0, tt);

if (card == tt) {
  Serial.print(numberArray[card]);
  Serial.print(" at ");
  Serial.print(tt);
  Serial.print(" is bad,");

  Serial.print(" but "); Serial.print(tt);
  Serial.print(" goes into array at ");
  Serial.println(card);

}
    numberArray[tt] = numberArray[card];
    numberArray[card] = tt;
  }
}


// Uniform Backward Inside-Out Fisher–Yates (safe)
void deal4()
{
  for (int tt = N - 1; tt >= 0; --tt) {
    const int card = random(tt, N);     // Arduino: [tt, N)

if (card == tt) {
  Serial.print(numberArray[card]);
  Serial.print(" at ");
  Serial.print(tt);
  Serial.print(" is bad,");

  Serial.print(" but "); Serial.print(tt);
  Serial.print(" goes into array at ");
  Serial.println(card);

}

    numberArray[tt] = numberArray[card];  // displace existing value    
    numberArray[card] = tt;               // insert new value
  }
}