int LEDpin=3;
int ldr=A0;
int buzzer = 8;
int value;
void setup() {
  Serial.begin(9600);
  pinMode(3, OUTPUT);
  pinMode(ldr, INPUT);
  pinMode(buzzer, OUTPUT);

  // put your setup code here, to run once:

}

void loop() {
  value=analogRead(ldr);
  Serial.print("ldr value is :");
  Serial.println(value);
  if(value>300) { //ldr value is greater than 300
   for (int fadeValue = 0; fadeValue <= 225; fadeValue +=5 ){
  analogWrite(LEDpin, fadeValue);
  delay(100); // waiting time for the dimming effect
  }
  }
  else if (value >=200){ //ldr value is greater than or equal to 200
  for (int sound = 1000; sound >=31; sound -=100){
    tone(buzzer, sound);
  }
  }
  else
  {
    analogWrite(LEDpin, 0); //ldr value is less than 200
    noTone(buzzer);
  }  
}
  // put your main code here, to run repeatedly: