int ledPins[8]={19,18,5,17,16,4,0,2};
void setup()

{
  Serial.begin(115200);
  Serial.println("HELLO, ESP32!");
  int i=0;
  while(i<8)
  {
    pinMode(ledPins[i], OUTPUT);
    i++;
  }
}
void loop()
{
  int j=0;
  while(j<8)
  {
    digitalWrite(ledPins[j], HIGH);
    j++;
  }
  delay(1000);
  int k=0;
  while(k<8)
  {
    digitalWrite(ledPins[k], LOW);
    k++;
  }
  delay(1000);
}