// Array in C/C++
const char codice[5] = {'1', 'a', '+', '$', '3'};
char seq[5];

void setup ()
{
  // put your setup code here, to run once:
  Serial. begin (115200);
  seq [0] = '1';
  seq[1] = 'a';
  seq[2] = '+';
  seq[3] = '$';
  seq [4] = '7';
}

void loop() 
{
  // put your main code here, to run repeatedly:
  for (int i = 0; i < 5; i++)
  {
    if (seq[i] != codice[i])
    {
      Serial.println("Sequenza errata");
      delay (500);
      return;
    }
  }
  Serial.println("Sequenza corretta");
  delay (500);
}