#include <Servo.h>

int servoPin = 9;
int ldrPin = A0;
int dt = 15;

Servo myServo;

void setup(){
myServo.attach(servoPin);
pinMode(ldrPin, INPUT);
Serial.begin(9600);
}

void loop(){
  int ldrval=analogRead(ldrPin);
  int servopos = map(ldrval,0,1023,0,180);
  if(servopos >=0 && servopos <=180){
    myServo.write(servopos);
    Serial.print("Moving to position: ");
    Serial.println(servopos);
  }
  else{
    Serial.println("Invalid input");
  }
}