//Include the servo motor library
 #include <Servo.h>
//Define the LDR sensor pins
 #define LDR1 A0 
 #define LDR2 A1
//Define the error value. You can change it as you like 7 
#define error 10
//Starting point of the servo motor
int Spoint=90;
//Create an object for the servo motor 
Servo servo;
void setup() 
{
//Include servo motor PWM pin 
servo.attach(11);
//Set the starting point of the servo
servo.write(Spoint); 
delay(1000);
}
void loop()
{
//Get the LDR sensor value
int ldr1 = analogRead(LDR1);
//Get the LDR sensor value
int ldr2 = analogRead(LDR2);
//Get the difference of these values
int value1 = abs(ldr1 - ldr2);
int value2 = abs(ldr2 - ldr1);
//Check these values using a if condition
if ((value1 <= error) || (value2<=error))
{

}
else {
  if(ldr1>ldr2){

  Spoint=--Spoint;
  }
if(ldr1<ldr2){

  Spoint=++Spoint;
}
}
//Write values on the servo motor
servo.write(Spoint);
delay(80);
 }