I am doing an assignment where I have to create a class Day that needs to do a series of things. I have everything figured out, most of it is pretty simple, but I am having one problem. One of the methods is supposed to let you set the day to whatever day of the week you want. For example, the program starts with the day set to Fri and I should be able to enter Mon and then tell it to output and it should output Mon. For some reason, it is not updating the day and I can't figure it out. Anybody see what I'm missing here?

```
The purpose of this program is to create a class Day that will perform
   multiple tasks regarding the day of the week. */

import java.util.*;

public class DayProgram
{
   static Scanner keyboard = new Scanner(System.in);

   public static class Day
   {
       String[] weekDays = {"Sun" , "Mon", "Tues", "Weds", "Thurs", "Fri", "Sat"};

      int setDay = 0;
      int returnDay = 0;

      public Day(String today)
      {
         for (int i = 0; i < weekDays.length; i++)
         {
            if (today.equals(weekDays[i]))
               {
                  setDay = i;
                  return;
               }
         }
         System.out.println("That is not a valid day.");
      }

      public void printDay()
      {
         if (setDay <= weekDays.length)
         {
            System.out.println("Today is " + weekDays[setDay]);
         }
         else System.out.println("Day is not valid");
      }

      public String setDay()
      {
         String newDay = keyboard.next();
         return newDay;
      }

      public String tomorrow()
      {
         return weekDays[(setDay + 1)%weekDays.length];
      }

      public String yesterday()
      {
         return weekDays[(setDay - 1)%weekDays.length];
      }

      public String findDay(int x)
      {
         return weekDays[(setDay + x)%weekDays.length];
      } 

      public String returnDay()
      {
         return weekDays[setDay];
      }

     }
   public static void main(String[] args)
   {
       Day day = new Day("Fri");

       day.printDay();

       System.out.println("Please change the day of the week.");

       day.setDay();

       day.printDay();

       System.out.println(day.returnDay());

       System.out.println(day.tomorrow());

       System.out.println(day.yesterday());

       System.out.println("Please enter number of days and I will tell you what day of the week it will be.");

       System.out.println(day.findDay(keyboard.nextInt()));

    }        
}

```