#define PIN_POTENTIOMETER A5

template<int samplesNum>
class AverageFilter
{
  public:
  AverageFilter(int pin)
  {
    pinIn = pin;
  }

  int operator()()
  {
    sum -= samples[curIndex];
    samples[curIndex] = analogRead(pinIn);
    sum += samples[curIndex];
    curIndex = (curIndex + 1) % samplesNum;  
    return sum/samplesNum;
  }

  private:
  int pinIn;
  double sum = 0;
  double samples[samplesNum]{};
  int curIndex = 0;
};

AverageFilter<10> filter(PIN_POTENTIOMETER);

void setup() 
{
  pinMode(PIN_POTENTIOMETER, INPUT);
  analogReference(DEFAULT);
  Serial.begin(9600);  
}

void loop() 
{
  int degree = map(filter(), 0, 1023, -135, 135);  
  Serial.println(degree);
  delay(100);
}