#include "LiquidCrystal_I2C.h"

const int trigPin = 6;
const int echoPin = 5;

float duration, distance;
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);

  lcd.begin();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Distance");
}

void int_lcd(int row, int column, double num, int fp, String txt) {
  lcd.setCursor(column, row);
  lcd.print(num, fp);

  // clear error display
  if( num < 10) column = column + fp + 2;
  else if( (num >= 10) && (num < 100) ) column = column + fp + 3;
  else if( (num >= 100) && (num< 1000) ) column = column + fp + 4;
  else if( (num >= 1000) && (num< 10000) ) column = column + fp + 5;
  lcd.setCursor(column, row);
  lcd.print(txt + "        ");

}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = (duration*.0343)/2;
  Serial.print("Distance: ");
  Serial.println(distance);
  int_lcd(1, 0, distance, 2, " cm.");
  delay(100);
}