import java.util.Calendar;
import java.util.GregorianCalendar;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

/** a simple demo to check whether a certain date is a Monday or not */

public class DayOfWeekChecker2 {

    public static void printUsageAndQuit() {
	    System.err.println("Usage: java DayOfWeekChecker mm/dd/yy");
	    System.exit(1);
    }

    public static void main(String [] args) {

	if (args.length!=1){
	    printUsageAndQuit();
	}

	String [] split = args[0].split("/");

	if (split.length != 3) {
	    printUsageAndQuit();
	}

	int m=0; int d=0; int y=0;

	try {
	    m=Integer.parseInt(split[0]);
	    d=Integer.parseInt(split[1]);
	    y=Integer.parseInt(split[2]);
	} catch (NumberFormatException nfe) {
	    printUsageAndQuit();
	}

	System.out.printf("%d/%d/%d\n",m,d,y);

	Calendar c = Calendar.getInstance();

	c.set(java.util.Calendar.YEAR, y);
	c.set(java.util.Calendar.MONTH, m - 1);  // the month designators are off by one
	c.set(java.util.Calendar.DAY_OF_MONTH, d);

	int day = c.get(java.util.Calendar.DAY_OF_WEEK);

	if (day != java.util.Calendar.MONDAY) {
	    throw new IllegalArgumentException("Date should be a Monday");
	}

	System.out.println("day="+day);
	System.out.println("\n\n\n");
	System.out.println("cal="+c);

	
	// Print dates of the current week starting on Monday to Friday
	DateFormat df = new SimpleDateFormat("EEE dd/MM/yyyy");

	System.out.println(df.format(c.getTime()));
    
	switch(day) {
	case java.util.Calendar.MONDAY: System.out.println("Monday"); break;
	case java.util.Calendar.TUESDAY: System.out.println("Tuesday"); break;
	case java.util.Calendar.WEDNESDAY: System.out.println("Wednesday"); break;
	case java.util.Calendar.THURSDAY: System.out.println("Thursday"); break;
	default: System.out.println("Not MTWR.  So there"); break;
	    
	} // end switch


    } //end main



}