// Bibliotheken
#include <LiquidCrystal_I2C.h>
#include <RTClib.h>
#include <Wire.h>

// Variablen
#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4
char daysOfTheWeek[7][12] = {"Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag"};

// Objekte
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);
RTC_DS1307 rtc;

void setup() {
  // put your setup code here, to run once:
  lcd.init();
  lcd.backlight();
  rtc.begin();
}

void loop() {
  // put your main code here, to run repeatedly:
  DateTime now = rtc.now();
  lcd.setCursor(0,0); lcd.print("Datum: ");
  lcd.print(now.day()); lcd.print("."); 
  lcd.print(now.month()); lcd.print("."); 
  lcd.print(now.year());
  lcd.setCursor(0,1); lcd.print("Uhrzeit: ");
  lcd.print(now.hour()); lcd.print(":"); 
  lcd.print(now.minute()); lcd.print(":"); 
  lcd.print(now.second());
  lcd.setCursor(0,2);
  lcd.print(daysOfTheWeek[now.dayOfTheWeek()]);
  delay(100);
}