Final - Range finder

#include <TM1637.h> // include display header file
#include <Ultrasonic.h> // include ultrasonic.h header
const int CLK = 2; // set clk pin
const int DIO = 3; // set dio pin
const int Echo = 4; // set echo pin
const int Trig = 5; // set trig pin
const int SO = 9; // set serial out control pin
const int led = 13; // set board led pin
TM1637 tm1637(CLK,DIO); // initalize display and pins
Ultrasonic ultrasonic(Trig,Echo); // initalize rangefinder pins
int seg0 = 0; // setting var to be used later
int seg1 = 0;
int seg2 = 0;
void setup() {
  Serial.begin(9600); // set serial display
  tm1637.init(); // initalize display
  tm1637.set(2); // set brightness of display
  pinMode(led, OUTPUT); // set led pin to output
  pinMode(SO, INPUT_PULLUP); // set SO as input pin
}
void loop() {
  digitalWrite(led, HIGH); // turn on led
  int SR = ultrasonic.Ranging(INC); // set SR to the sensor reading INC is for inch measurment
  if (SR >= 100) { // setting seg0-2 if SR is over 100
    seg0 = SR / 100; // SR devided by 100 gives first digit
    seg1 = SR / 10; // SR devided by 10 givese second digit
    seg2 = SR % 10; // SR % 10 gives last digit
  }
  else if (SR <= 99) { // setting seg0-2 if SR is under 100 but over 10
    seg0 = 0; // set first digit to 0
    seg1 = SR / 10; // SR devided by 10 givese second digit
    seg2 = SR % 10; // SR % 10 givese second digit
  }
  else {// setting seg0-2 if SR is under 10
    seg0 = 0; // setting first digit to 0
    seg1 = 0; // setting second digit to 0
    seg2 = SR; // SR %10 givese second digit
  }
  tm1637.display(0,seg0); // display first range digit on segment 0
  tm1637.display(1,seg1); // display second range digit on segment 1
  tm1637.display(2,seg2); // display third range digit on segment 2
  tm1637.display(3,16); // display - on segment 3
  if (digitalRead(SO) == LOW) { // if SO is high we will start a serial display
    Serial.print(ultrasonic.Ranging(INC)); // read sensor
    Serial.println(" Sensor Reading ");
    Serial.print(SR); // read stored value from sensor
    Serial.println(" SR var set ");
    Serial.print(seg0); //print all seg to serial
    Serial.print(seg1);
    Serial.print(seg2);
    Serial.println(" Display ");
    Serial.print(digitalRead(SO));
    Serial.println(" Serial Output ");
  }
  else ;
  digitalWrite(led, LOW); // turn off led
  delay(5000); // 5 second display
}