#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

int distance, duration;

void setup() {
  lcd.init();
  lcd.clear();
  lcd.backlight();
  lcd.setCursor(0,0);
  pinMode(0, OUTPUT);
  pinMode(4, INPUT);
}

void loop() {
  lcd.clear();
  lcd.print("Distance:\n");
  digitalWrite(0, HIGH);
  delayMicroseconds(2);
  digitalWrite(0, LOW);
  duration = pulseIn(4, HIGH);
  distance = duration*0.017;
  lcd.print(distance);
  lcd.print("cm");
  delay(1000);
}