Odtnhj

I'm creating a Calendar for my CS class and need to be able to get my calendar months to start on the correct day of the week. My first go at trying to solve this problem looked something like this:

public static int getStartingDay(int month) {

if (month == 1 || month == 10) 

return (18 + 4) % 7;

 else if (month == 2 || month == 3 || month == 11) 

return ((18 + 4 + 3)) % 7;

 else if (month == 4 || month == 7) 

return ((18 + 4 + 6)) % 7;

 else if (month == 9 || month == 12) 

return ((18 + 4 + 5) % 7);

 else if (month == 5) 

return ((18 + 4 + 1) % 7);

 else 

return ((18 + 4 + 1) % 7);

I was really happy to see that this was working but when I showed this to my teacher he said it could be done in a much simpler way.

He responded:

"First of all, I want you to recall that I stated we are just concerned with 2018. Therefore, we only need to know what day 2018 started on. From there, we can basically do what we did for the second writing code question on the midterm, where given a day out of 365 for the year, we can determine what day of the week that falls on. This means that all we have left to do it determine what day out of 365 that a given month falls on. This can be done with some addition if we know how many days are in each month. We can just add up all of the previous month's days to get what day our month starts on. "

For the midterm, we were to assume that the year started on Wednesday (3rd day of the week) so my solution looked like this:

Method call : dayOfYear(5); Should return: 0 for Sunday

Public static final int FIRST_DAY_OF_YEAR = 3;

Public static int dayOfTheWeek(int day)

return (firstDay + day –1)%7;

Result: 0 (Sunday)

I'm a bit lost on how these two problems are connected. I know the key in my teacher's response was:

"This means that all we have left to do it determine what day out of 365 that a given month falls on." If you could help me understand how to solve this problem, you would be helping me tremendously!

I should also add, We are not allowed to use Java's Calendar object to get this working properly!

Here is my current Project:

 import java.util.*;
 public class CalendarReformed 
 // Here we can change the size of the calendar
 public static final int FIRST_DAY_OF_MONTH = 1;
 private static final int SIZE = 7;

 public static void main(String args)
 Scanner console = new Scanner(System.in);
 int day = -1;
 int month = -1;
 String userSelection;
 boolean flag = true;

 while (flag)

 userMenu();
 userSelection = console.next();
 if (userSelection.equalsIgnoreCase("e"))
 System.out.print("Please enter a date:(mm/dd) ");
 String date = console.next();
 month = monthFromDate(date);
 day = dayFromDate(date);
 int highlightSelectedDay = day;
 displayCalendar(month, highlightSelectedDay);

 else if (userSelection.equalsIgnoreCase("t"))
 Calendar c = Calendar.getInstance();
 day = c.get(Calendar.DATE);
 month = c.get(Calendar.MONTH)+1;
 System.out.println("Today's date: " + month +"/"+ day);
 displayCalendar(month,day);
 else if (userSelection.equalsIgnoreCase("n"))
 if (day != -1 && month != -1)
 day = 1;

 month = grabNextMonth(month);
 displayCalendar(month,day);
 else
 System.out.print("You must have a month selected to go to next month!n");
 
 else if(userSelection.equalsIgnoreCase("p"))
 if (day != -1 && month != -1)
 day = 1;

 month = grabPreviousMonth(month);
 displayCalendar(month, day);
 else 
 System.out.print("You must first select a month for previous month to function!n");
 
 else if(userSelection.equalsIgnoreCase("q"))
 System.out.print("Now exiting the Calendar programn");
 System.out.print("Have a nice day!");
 flag = false;
 else 
 System.out.print(" *USER ERROR DETECTED* n");
 System.out.println("Please make a valid selection from the menu!");
 
 

 

 // This method will print the month digit and centers it
 public static void drawMonth(int month, int daysToSkip, int maxDays)
 System.out.println();
 int placeMonth = (SIZE * 3)-4;
 for (int space = 1; space <= placeMonth; space++)
 printSpaces(1);
 
 String monthHolder;
 if (month == 1)
 monthHolder = "*January*";
 else if(month == 2)
 monthHolder = "*February*";
 else if (month == 3)
 monthHolder = "*March*";
 else if (month == 4)
 monthHolder = "*April*";
 else if (month == 5)
 monthHolder = "*May*";
 else if (month == 6)
 monthHolder = "*June*";
 else if (month == 7)
 monthHolder = "*July*";
 else if (month == 8)
 monthHolder = "*August*";
 else if (month == 9)
 monthHolder = "*September*";
 else if (month == 10)
 monthHolder = "*October*";
 else if (month == 11)
 monthHolder = "*November*";
 else 
 monthHolder = "*December*";
 
 System.out.println(monthHolder);

 drawArt();

 int start = 1;
 while (start <= maxDays) 
 if (start == 1) 
 drawRow(start, maxDays, daysToSkip);
 start += 7 - daysToSkip;
 else 
 drawRow(start, maxDays, 0);
 start += 7;
 
 

 // Displays the top of the calendar border
 for (int i = 1; i <= SIZE * 7; i++)
 System.out.print("_");
 
 

 // This method prints one row of our calendar and applies our