C / C++ / MFC

I hope that someone can help me.
            
I am currently working on developing a flight simulator with force feedback. To do the calculations of the force feedback, we need to know the position of vertical yoke that we are using. We use two potentiometers to detect the position of the yoke for roll and pitch. The potentiometers are connected with Arduino Uno that will change analog values to digital values:

int pinpotRoulis=A0; //analog input 0
 int valpotRoulis=0;
 int valmancheRoulis=0;
 int mapRoulis =0;
 int pinpotTangage=A5; //analog input 0
 int valpotTangage=0;
 int valmancheTangage=0;
 int mapTangage =0;
 int voltage = 8;
void setup() {
  Serial.begin(115200);
  pinMode(voltage,OUTPUT);
  digitalWrite(voltage,HIGH);


}
void loop() {

    char dataToSend[20];

    valpotRoulis = analogRead(pinpotRoulis);       

    valpotTangage = analogRead(pinpotTangage);       

    sprintf(dataToSend, "R%dE T%dE", valpotRoulis, valpotTangage);
    Serial.println(dataToSend);
    printf("%s\n", dataToSend);

    delay(10);

}

void MainWindow::getPotentiometreFFB(){

  do{
    n = RS232_PollComport(cport_nr, (unsigned char *) str_recv, (int)BUF_SIZE);
    i++;
  }while(n <= 0 && i < 1000000);

    if(n > 0){
      str_recv[n] = 0;
      printf("Received %i bytes: '%s'\n", n, str_recv);



      position = -1;
        // Récupération roulis
         for (int j = 0; j < n ; j++)
         {
            if(str_recv[j]=='R') {
               position = j;
                break;
            }
            position = -1;
         }
         /////////////modif////////
         if (position != -1) {
             for (int k = 0;k<5;k++)
            {
             valeur_R[k] = str_recv[position+k];
            }


            char * ptrsuite_1Chaine = NULL;
            ptrsuite_1Chaine = strchr(valeur_R, 'E');
            if (ptrsuite_1Chaine != NULL)
                {
                    sscanf(valeur_R,"R%dE",&valRoulis);

                    valRoulis = minMaxPotentiometre(450, 650, valRoulis);

                    m_data.roll_cmd = mappingPotentiometreRoulis(valRoulis);
            }
        }


         position = -1;
        //Récupération tangage
        for (int j = 0; j < n ; j++)
        {
           if(str_recv[j]=='T') {
              position = j;
               break;
           }
           position = -1;
        }
        if (position != -1) {
            for (int k = 0;k<5;k++)
            {
               valeur_T[k] = str_recv[position+k];
            }

            char * ptrsuite_2Chaine = NULL;
            ptrsuite_2Chaine = strchr(valeur_T, 'E');

            if (ptrsuite_2Chaine != NULL)
            {
                    sscanf(valeur_T,"T%dE",&valTangage);

                    valTangage = minMaxPotentiometre(100, 340, valTangage);

                    m_data.pitch_cmd = -mappingPotentiometreTangage(valTangage);
            }



        }

      cout<< "Val roulis :" << m_data.roll_cmd << endl;
      cout<< "Val tangage :" << m_data.pitch_cmd << endl;

      ui->roll_cmd->setValue(m_data.roll_cmd);
      ui->pitch_cmd->setValue(m_data.pitch_cmd);

    }else{
        cout << "No data Roulis tangage" << endl;
    }


}