new to Ardunio but trying to compile

const int micPin = A0;          //MIC PORT
const int LedPin = LED_BUILTIN; //FLASH BUILT IN LED
const int numberOfSamples = 128; //NUMBER OF READINGS
const int middleValue = 512;    //MIDDLE OF RANGE

int sample;                     //VALUE FROM MIC
long Signal;                    //READING AFTER DC OFFSET
long newReading;                //AVERAGE OF LOOP READINGS

long runningAverage = 0;          //CACULATED VALUES
const int averagedOver = 16;    //HOW QUICK NEW VALUES AFFECT RUNNING AVG

const int threshold = 400;       //AT WHAT LEVEL LED COMES ON

void setup()
{
  pinMode(LedPin, OUTPUT);      //
  Serial.begin(9600);
}
// put your setup code here, to run once:


void loop()
{
  long sumOfSquares = 0;
  for (int I = 0; I < numberOfSamples; I++) { //average readings
    sample = analogRead(micPin);              //take a reading
    Signal = (sample - middleValue);
    Signal *= Signal;                         //SQUARE IT
    sumOfSquares += Signal;                   //add to the total
  }
  newReading = sumOfSquares / numberOfSamples;

  //caculate running average
  runningAverage = (((averagedOver - 1) * runningAverage) + newReading) / averagedOver;

  Serial.print("new:"); Serial.print(newReading);
  Serial.print(".");
  Serial.print("running:");
  Serial.printin(runningAverage);

  if (runningAverage > threshold) {           //is average more than threshold?
    digitalWrite(LedPin, HIGH);
  } else {
    digitalWrite(LedPin, LOW;
  }

}




// put your main code here, to run repeatedly:

}

const int micPin = A0;          //MIC PORT
const int LedPin = LED_BUILTIN; //FLASH BUILT IN LED
const int numberOfSamples = 128; //NUMBER OF READINGS
const int middleValue = 512;    //MIDDLE OF RANGE

int sample;                     //VALUE FROM MIC
long Signal;                    //READING AFTER DC OFFSET
long newReading;                //AVERAGE OF LOOP READINGS

long runningAverage = 0;          //CACULATED VALUES
const int averagedOver = 16;    //HOW QUICK NEW VALUES AFFECT RUNNING AVG

const int threshold = 400;       //AT WHAT LEVEL LED COMES ON

void setup()
{
  pinMode(LedPin, OUTPUT);      //
  Serial.begin(9600);
}
// put your setup code here, to run once:


void loop()
{
  long sumOfSquares = 0;
  for (int i = 0; i < numberOfSamples; i++) { //average readings .. .. .. .. ( NORMALLY I is lowercase )
    sample = analogRead(micPin);              //take a reading
    Signal = (sample - middleValue);
    Signal *= Signal;                         //SQUARE IT
    sumOfSquares += Signal;                   //add to the total
  }
  newReading = sumOfSquares / numberOfSamples;

  //caculate running average
  runningAverage = (((averagedOver - 1) * runningAverage) + newReading) / averagedOver;

  Serial.print("new:"); Serial.print(newReading);
  Serial.print(".");
  Serial.print("running:");
  Serial.println(runningAverage);

  if (runningAverage > threshold) {           //is average more than threshold?
    digitalWrite(LedPin, HIGH);
  } else {
    digitalWrite(LedPin, LOW);
  }
}