Moving Sensor Parking System

#include <Servo.h>
Servo servo;
int trigPin = 8;    // Trigger
int echoPin = 9;    // Echo
long duration, cm, inches;
long h;
int pos = 0, distcm = 0,slot;
void setup()
{
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  servo.attach(10);
}

void loop()
{
  for (pos = 15; pos <= 135; pos += 40) //the servo will cover from 15 to 135 deg
  {
    servo.write(pos);
     delay(4910);
      h=radar();
    if(h>18)
    {
      slot=pos/40;
      Serial.println("empty and u can park on slot");Serial.println(slot);
    }
    else
    {
      slot=pos/40;
      Serial.println("not available on slot");
      Serial.println(slot);
    }
    
  }
  for (pos = 95; pos >= 55; pos -= 40)
  {
    servo.write(pos);
     delay(4910);
      h=radar();
     if(h>18)
    {
      slot=pos/40;
      Serial.println("empty and u can park on slot");
      Serial.println(slot);
    } 
     else
    {
      slot=pos/40;
      Serial.println("not available on slot");Serial.println(slot);
    }
  }
}
long radar(void) //calulate the distance
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(10);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
 
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
  cm = (duration/2) / 29.1;     
 
  return cm;
}