#define redled 7
#define greenled 6
#define ldrPin A0

void setup() {

  Serial.begin(9600);
  pinMode(redled, OUTPUT);
  pinMode(greenled, OUTPUT);
}

void loop() {
  int ldrStatus = analogRead(ldrPin);
  Serial.println(ldrStatus);
  if (ldrStatus >= 600) {
    digitalWrite(greenled, HIGH);
    digitalWrite(redled, LOW);
  }
  else {
    digitalWrite(redled, HIGH);
    digitalWrite(greenled, LOW);
  }
}