Help with a year planner.

Question

Hi there,
I've been trying to create a year planner and been advised to use zellers algorithm to ensure the correct date is placed in each cell of the planner.
the algorithm given was:
IF M is january or M is february
add 12 onto the M
subtract 1 from the year
that confused me..could anyone shed some light
then this
W=D+int(((M+1)*26)\10+y+Int(Y/4)+Int(C/4)+5*C
WD=( W MOD 7)
where:
D = day
M = month
Y = right two digits of the year
C = left two digits of the year
WD= week day (the remainder of (the modulus) of W divided by 7
it should return a value like:
0 for sat
1 for sunday
2 for monday etc
but what i dont understand is how to use that to create the cells and ensure the correct date is in each. Especially since months are shown at once.
can anyone shed some light on this?

Answer 1

I don't know what zellers algorithm is, but this is a display of the full year (with back/forward buttons for other years), if that is what you're after (needs testing).
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Calendar;
class YearPlanner extends JFrame implements ActionListener
  int year = Calendar.getInstance().get(Calendar.YEAR);
  JLabel days[][] = new JLabel[12][49];
  String weekdays[] = {"S","M","T","W","T","F","S"};
  JButton back = new JButton("<<< Back 1 Year");
  JButton forward = new JButton("Forward 1 Year >>>");
  JLabel lblYear;
  String sMonths[] = {"January","February","March","April","May","June","July",
                      "August","September","October","November","December"};
  public YearPlanner()
    super("Year Planner");
    setSize(900,485);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container frame = getContentPane();
    frame.setLayout(new BorderLayout());
    JPanel monthHolder = new JPanel(new GridLayout(2,6));
    JPanel month[] = new JPanel[12];
    for(int i = 0; i < month.length; i++) month[i] = new JPanel(new BorderLayout());
    JPanel monthName[] = new JPanel[12];
    for(int i = 0; i < monthName.length; i++) monthName[i] = new JPanel(new FlowLayout());
    JPanel monthDays[] = new JPanel[12];
    for(int i = 0; i < monthDays.length; i++) monthDays[i] = new JPanel(new GridLayout(7,7));
    JLabel lblMonths[] = new JLabel[12];
    for(int i = 0; i < days.length; i++)
      for(int ii = 0; ii < days.length; ii++)
days[i][ii] = new JLabel();
days[i][ii].setFont(new Font("Ariel",Font.BOLD,10));
days[i][ii].setPreferredSize(new Dimension(25,25));
if(ii < 7) days[i][ii].setText(" "+weekdays[ii]);
monthDays[i].add(days[i][ii]);
for(int i = 0; i < lblMonths.length; i++)
lblMonths[i] = new JLabel(sMonths[i]);
monthName[i].add(lblMonths[i]);
month[i].add(monthName[i],BorderLayout.NORTH);
month[i].add(monthDays[i],BorderLayout.SOUTH);
month[i].setBorder(BorderFactory.createEtchedBorder());
monthHolder.add(month[i]);
back.addActionListener(this);
forward.addActionListener(this);
JPanel lower = new JPanel();
lower.add(back);
lblYear = new JLabel(" Year Planner for "+year+" ");
lower.add(lblYear);
lower.add(forward);
frame.add(monthHolder,BorderLayout.NORTH);
frame.add(lower,BorderLayout.SOUTH);
setDates();
setLocation(100,100);
setVisible(true);
public void setDates()
Calendar cal = Calendar.getInstance();
for(int x = 0; x < days.length; x++)
for(int i = 7; i < days[x].length; i++)
days[x][i].setText("");
cal.set(year,x,1);
int firstDay = cal.get(cal.DAY_OF_WEEK)-1+7;
int ii = 1;
for(int i = firstDay; i<firstDay+31; i++)
if(ii < 10) days[x][i].setText(" "+ii);
else days[x][i].setText(""+ii);
ii++;
cal.add(cal.DATE,1);
if(ii > 27 && cal.get(Calendar.MONTH) != x) break;
lblYear.setText(" Year Planner for "+year+" ");
public void actionPerformed(ActionEvent ae)
if(ae.getSource() == back) year--;
else year++;
setDates();
public static void main(String args[]){new YearPlanner();}