[HaBo]

#include <stdio.h>
#include <time.h>

char *wday[] = {"Sunday",
                           "Monday",
                           "Tuesday",
                           "Wednesday",
                           "Thursday",
                           "Friday",
                           "Saturday",
                           "unknown day"
                           };

int main()
{
   struct tm time_check;
   int year, month, day;

/*input the date*/
   printf("year: ");
   scanf("%d", &year);
   printf("month: ");
   scanf("%d", &month);
   printf("day: ");
   scanf("%d", &day);

/*fill our structure*/
   time_check.tm_year = year - 1900;
   time_check.tm_mon = month -1;
   time_check.tm_mday = day;

   time_check.tm_hour = 0;
   time_check.tm_min = 0;
   time_check.tm_sec = 1;
   time_check.tm_isdst = -1;

/*get the day-nr.*/
   if (mktime(&time_check) == -1)
      time_check.tm_wday = 7;

   printf("This day was a %s\n", wday[time_check.tm_wday]);
 
   return 0;

}

--Schaltjahr?
FUN leapYear : nat -> bool
DEF leapYear(n) ==
IF n % 4 = 0 THEN true
IF n % 100 = 0 THEN false
IF n % 400 = 0 THEN true
ELSE false

FUN leapDay : date -> nat
DEF leapDay(d)==IF leapYear? (year(d)) THEN 1 ELSE 0 FI

-- Tage im Monat
FUN daysOfMonth : date -> nat
DEF daysOfMonth(d)==
IF month(d) = 2 THEN 28 + leapDay(d)
IF month(d) < 8 THEN 30 + month(d) % 2
ELSE 31 - month(d) % 2 FI

-- Tage, die seit 0 vergangen sind
FUN daysOfLord : date -> nat
DEF daysOfLord(d)==
IF d > 1 THEN 1 + daysOfLord(date(day(d) - 1,month(d),year(d)))
IF m > 1 THEN daysOfMonth(date(day(d),month(d) - 1,year(d)) +
daysOfLord(date(day(d), month(d) - 1, year(d)))
IF y > 1 THEN 365 + leapDay(date(day(d), month(d), year(d) - 1)) +
daysOfLord(date(day(d), month(d), year(d) - 1))
ELSE 0 FI

-- Tage zwischen zwei Daten
FUN daysBetween: date ** date -> nat
DEF daysBetween(d1,d2)==
IF daysOfLord(d1) - daysOfLord(d2) > 0 THEN daysOfLord(d1) -
daysOfLord(d2)
ELSE daysOfLord(d2) - daysOfLord(d1) FI

-- der erste Januar 1950 war ein Sonntag
FUN dayOfWeek : date -> nat
DEF dayOfWeek(d) == daysBetween(d, date(1,1,1950)) % 7

public class Main {

	public static void main(String[] args) {	
		System.out.println(new Weeklist().getDayname(((System.currentTimeMillis() / 1000) / 86400) % 7));
	}

}

public class Weeklist {

	private ArrayList<String> days = null;
	
	public Weeklist() {
		this.days = new ArrayList<String>();
		this.addDays();
	}
	
	private void addDays() {
		days.add("Donnerstag");
		days.add("Freitag");
		days.add("Samstag");
		days.add("Sonntag");
		days.add("Montag");
		days.add("Dienstag");
		days.add("Mittwoch");
	}
	
	public String getDayname(long idx) {
		return days.get((int)idx);
	}
	
}

days = [ "Donnerstag", "Freitag", "Samstag", "Sonntag", "Montag", "Dienstag", "Mittwoch" ]
time = System.currentTimeMillis() / 1000
println days[ (int)(time / 86400) % 7 ]