Thread: Need some help testing created class.

I was assigned a problem where I have to create a class called Day. The program is to store the day such as Sun for Sunday, Mon for Monday, etc. The program then preform the following steps:

1. Set the Day
2. Print the Day
3. Return the Day
4. Return the Next Day
5. Return the Previous Day
6. Calculate and return the day by adding certain days to the current day. For example, if the current day is Monday and we add four days, the day to be returned is Friday.

I have wrote some code for the Day class and the Daytester class but it isn't working very well and I can't figure out how I'm going to implement the part where it adds an integer and returns the Day.
I'm just not very good with creating my own classes just yet.

Here is the Day class that I have written so far:

public class Day
{
  private int Day;
  private String Sun,Mon,Tues,Wed,Thurs,Fri,Sat;
 
  public Day()
  {
    Sun = "";
    Mon = "";
    Tues = "";
    Wed = "";
    Thurs = "";
    Fri = "";
    Sat = "";
  }
 
  public Day(int Day)
  {
    if(Day == 1)
      Sun = "Sunday";
    else if(Day == 2)
      Mon = "Monday";
    else if(Day == 3)
      Tues = "Tuesday";
    else if(Day == 4)
      Wed = "Wednesday";
    else if(Day == 5)
      Thurs = "Thursday";
    else if(Day == 6)
      Fri = "Friday";
    else if(Day == 7)
      Sat = "Saturday";
   }
 
  public void setDay(int Day)
  {
    this.Day = Day;
  }
 
  public int getDay()
  {
    return this.Day;
  }
 
  public void printDay(int Day)
  {
    if(Day == 1)
      System.out.println("Today is " + Sun);
    else if(Day == 2)
      System.out.println("Today is " + Mon);
    else if(Day == 3)
      System.out.println("Today is " + Tues);
    else if(Day == 4)
      System.out.println("Today is " + Wed);
    else if(Day == 5)
      System.out.println("Today is " + Thurs);
    else if(Day == 6)
      System.out.println("Today is " + Fri);
    else if(Day == 7)
      System.out.println("Today is " + Sat);
    }
 
  public void printYesterday(int Day)
  {
    if(Day == 1)
      System.out.println("Yesterday was " + Sat);
    else if(Day == 2)
      System.out.println("Yesterday was " + Sun);
    else if(Day == 3)
      System.out.println("Yesterday was " + Mon);
    else if(Day == 4)
      System.out.println("Yesterday was " + Tues);
    else if(Day == 5)
      System.out.println("Yesterday was " + Wed);
    else if(Day == 6)
      System.out.println("Yesterday was " + Thurs);
    else if(Day == 7)
      System.out.println("Yesterday was " + Fri);
   }
 
  public void printTomorrow(int Day)
  {
    if(Day == 1)
      System.out.println("Tomorrow is " + Mon);
    else if(Day == 2)
      System.out.println("Tomorrow is " + Tues);
    else if(Day == 3)
      System.out.println("Tomorrow is " + Wed);
    else if(Day == 4)
      System.out.println("Tomorrow is " + Thurs);
    else if(Day == 5)
      System.out.println("Tomorrow is " + Fri);
    else if(Day == 6)
      System.out.println("Tomorrow is " + Sat);
    else if(Day == 7)
      System.out.println("Tomorrow is " + Sun);
  }
}

And here is the Daytester so far:

import java.util.*;
 
public class DayTester
{
  public static void main(String[] args)
  {
    Scanner input = new Scanner(System.in);
    int Day,x;
    Day Dayweek;
 
    System.out.println("Enter a number 1-7 corresponding to the day of the week, for example, Sunday is 1, Monday is 2, .. Saturday is 7");
    Day = input.nextInt();
    Dayweek = new Day(Day);
    Dayweek.setDay(Day);
    System.out.println(Dayweek);
  }
}

I appreciate any help guys!

Do you know or can you use Arrays yet?

Your constructor is a little twisted. You won't set the variables 'Mon' through 'Sun' based on the parameter Day (which should be called 'day'). In fact, there won't be variables 'Mon' through 'Sun'. You'll set the day object's name that will be a field, like:

String name;

This really isn't a bad start, but your thinking needs to be modified a bit on what the class Day is, what fields it needs, and how to set, get, and display those fields according to the requirements you've been given. And I really need to know if you know and can use Arrays. If not, the math part of the problem becomes a lot harder.

Originally Posted by GregBrannon

Do you know or can you use Arrays yet?

Your constructor is a little twisted. You won't set the variables 'Mon' through 'Sun' based on the parameter Day (which should be called 'day'). In fact, there won't be variables 'Mon' through 'Sun'. You'll set the day object's name that will be a field, like:

String name;

This really isn't a bad start, but your thinking needs to be modified a bit on what the class Day is, what fields it needs, and how to set, get, and display those fields according to the requirements you've been given. And I really need to know if you know and can use Arrays. If not, the math part of the problem becomes a lot harder.

We started learning about arrays in our last class so I know the basics of an array.

Good. Then this is what I recommend you do:

Create an array constant, something like:

String[] DAY_OF_WEEK = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };

Then in your constructor,

String name;
int dayNumber;
 
void Day( int dayNumber )
{
    // set the name of the day to the element at the index dayNumber
    this.dayNumber = dayNumber;
    name = DAY_OF_WEEK[dayNumber]
 
    // the rest of the constructor . . .
}

And then the math part of the assignment becomes simple. The number of the next day is ( dayNumber + 1 ) % 7. You figure out the day before, 4 days from now, etc.

Come back after you've made those changes and need more help.