This sample code is for DS18B20 Waterproof Temperature Sensor Tutorial.

DS18B20.ino

// Include the libraries we need
#include <OneWire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal_I2C.h>

#define ONE_WIRE_BUS 9
float Celsius = 0;
float Fahrenheit = 0;

LiquidCrystal_I2C lcd(0x27, 20, 2);  // set the LCD address to 0x27 for a 16 chars and 2 line display
OneWire oneWire(ONE_WIRE_BUS);       // Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
DallasTemperature sensors(&oneWire); // Pass our oneWire reference to Dallas Temperature.

void setup() {
  lcd.init();
  lcd.backlight();
  sensors.begin();
  Serial.begin(9600);
}

void loop() {
  sensors.requestTemperatures();

  Celsius = sensors.getTempCByIndex(0);
  Fahrenheit = sensors.toFahrenheit(Celsius);

  Serial.print(Celsius);
  Serial.print(" C  ");
  Serial.print(Fahrenheit);
  Serial.println(" F");

  lcd.setCursor(2, 0);
  lcd.print("TEMPERATURE");
  lcd.setCursor(0, 1);
  lcd.print((char)223);
  lcd.setCursor(1, 1);
  lcd.print("C:");
  lcd.setCursor(3, 1);
  lcd.print(Celsius, 1);   //display the temperature in 1 decimal place
  lcd.setCursor(8, 1);
  lcd.print((char)223);
  lcd.setCursor(9, 1);
  lcd.print("F:");
  lcd.setCursor(11, 1);
  lcd.print(Fahrenheit, 1); //display the temperature in 1 decimal place

  delay(1000);

}