60. Arduino UART Buffer

What will be the value of receivedData[0] and receivedData[99]? (after executing the following code)

uint8_t receivedData[100];
int index = 0;

void setup() {
  Serial.begin(9600);

  for (int i = 1; i <= 100; i++)  {
    Serial.write(i);
    delay(4);
  }
}

void loop() {
  while (Serial.available() > 0) {
    receivedData[index] = Serial.read();
    index++;
  }
}