Question

I am having problems with my java assignment. I have been working on it for 2 weeks and could really use some help.

Here is the problem:

1. Create a console (standalone) application. This program will allow
   you to select MegaBall lottery
   numbers. For the first 5 numbers you
   will be requested to enter a number
   that is greater than zero and less
   than or equal to 56. However, there’s
   a catch! Each number must be
   different.

2. When any of the first five numbers is less than 0 or greater than 56 the
   user will receive a message to this
   effect and will be asked to reenter
   the number. You will create the code
   that will display one message when a
   number less than 1 is entered and a
   different message if a number greater
   than 56 is entered.

   If the
   number is the same as any number
   entered before it (with the exception
   of the megaball number) the user will
   receive a message to this effect and
   asked to reenter the number. This is
   the same for the second through fifth
   numbers. I typed in the same number a
   couple of times so you will see what
   occurs when I do.

3. When entering the megaball number, if the number entered IS NOT between 1
   and 46 then the user will receive a
   message to this effect and asked to
   reenter the number. One message will
   display if the number is less than 1,
   and a different if the number is
   greater than 46.

The following MUST be included in the
program:

• You must have multiple classes. One that contains the accessor and mutator
  methods, a readInput() method and a
  writeOutput() method. You will not use
  the mutator methods but include them
  anyway to show that you know how to
  write them. Name this first program
  “Megaball.java”.
• The second program is to be named “MegaballTest.java” and will be
  responsible for creating a Megaball
  object and calling the writeOutput()
  and readInput() methods from the
  Megaball class.

Here is my solutions:

import java.util.Scanner;

public class Megaball
{
 Scanner scan = new Scanner(System.in);
 double n1, n2, n3, n4, n5, n6;
 double Num;
 String readInput;
 String writeOutput;

 public Megaball()
 {
  n1 = 0;
  n2 = 0;
  n3 = 0;
  n4 = 0;
  n5 = 0;
  n6 = 0;
 }

 public Megaball(double n1, double n2, double n3, double n4, double n5, double n6)
 {
  this.n1 = n1;
  this.n2 = n2;
  this.n3 = n3;
  this.n4 = n4;
  this.n5 = n5;
  this.n6 = n6;
 }

 public double getNum()
 {
  return Num;
 }

 public void setNum(double n1, double n2, double n3, double n4, double n5, double n6)
 {
  this.Num = Num;
 }

 public String readInput()
 {
  return readInput;
 }

 public String writeOutput()
 {
  return writeOutput;
 }

}




public class MegaballTest
{
 public static void main(String[] args)
 {
  Megaball n1 = new Megaball(0,0,0,0,0,0);
  Megaball n2 = new Megaball(0,0,0,0,0,0);
  Megaball n3 = new Megaball(0,0,0,0,0,0);
  Megaball n4 = new Megaball(0,0,0,0,0,0);
  Megaball n5 = new Megaball(0,0,0,0,0,0);
  Megaball n6 = new Megaball(0,0,0,0,0,0);

 do
 {
 System.out.println("Please enter your 1st number which is between 0 and 56");
 if (n1 < 0 || n1 > 56)
 System.out.println("Number must be between 0 and 56");
 }while (n1 < 0 || n1 > 56);
 System.out.println("Please enter your 2nd number which is between 0 and 56");

}
}

On the test… I wanted to make sure the first number worked before I did the rest. Here is the error I keep getting:

G:\MegaballTest.java:15: operator < cannot be applied to Megaball,int
 if (n1 < 0 || n1 > 56)
        ^
G:\MegaballTest.java:15: operator > cannot be applied to Megaball,int
 if (n1 < 0 || n1 > 56)
                  ^
G:\MegaballTest.java:17: operator < cannot be applied to Megaball,int
 }while (n1 < 0 || n1 > 56);
            ^
G:\MegaballTest.java:17: operator > cannot be applied to Megaball,int
 }while (n1 < 0 || n1 > 56);
                      ^
4 errors

Tool completed with exit code 1

Thanks so much!!

Answer 1

1. Create a console (standalone) application. This program will allow
   you to select MegaBall lottery
   numbers. For the first 5 numbers you
   will be requested to enter a number
   that is greater than zero and less
   than or equal to 56. However, there’s
   a catch! Each number must be
   different.

There is a sequence here and the values are integers. Consider the use an array (int[]) or a List (ArrayList<Integer>).

1. When any of the first five numbers is less than 0 or greater than 56 the
   user will receive a message to this
   effect and will be asked to reenter
   the number. You will create the code
   that will display one message when a
   number less than 1 is entered and a
   different message if a number greater
   than 56 is entered.

   If the
   number is the same as any number
   entered before it (with the exception
   of the megaball number) the user will
   receive a message to this effect and
   asked to reenter the number. This is
   the same for the second through fifth
   numbers. I typed in the same number a
   couple of times so you will see what
   occurs when I do.

Consider the following member variable:

ArrayList<Integer> numbers; (using an ArrayList is simpler to “grow”).

Then consider the functions int readNumber(): Perform the above logic (reading from input and displaying the messages). Returns -1 if an invalid number is selected, else returns the number in the appropriate range. Inside readNumber, make sure the number does not currently exist in the numbers list (remember, numbers is a member variable).

1. When entering the megaball number, if the number entered IS NOT between 1
   and 46 then the user will receive a
   message to this effect and asked to
   reenter the number. One message will
   display if the number is less than 1,
   and a different if the number is
   greater than 46.

The mega-ball is different in that it can be a repeat and the range is different.

So, consider the function int readPowerballNumber(): Perform the above logic (reading from input and displaying the messages). Returns -1 if an invalid number is selected, else returns the number in the appropriate range.

Now, having those two, the following pseduo-code can be employed:
This might be the code in the readInput() member. Remember that numbers is a member variable. Also note that it farms out the work to the “helper” methods which employ the logic for reading and displaying the warning, etc.

set numbers = an empty list

while have less than 5 numbers:
  number = readNumber()
  if number is not -1:
    append number to numbers     

while have less than 6 numbers:
  number = readPowerballNumber()
  if number is not -1:
    append number to numbers

// at this point, all 6 numbers are valid and loaded
// you may then call `writeOutput()` to write all the numbers

The following MUST be included in the
program:

• You must have multiple classes. One that contains the accessor and mutator
  methods, a readInput() method and a
  writeOutput() method. You will not use
  the mutator methods but include them
  anyway to show that you know how to
  write them. Name this first program
  “Megaball.java”.

I have no idea why this “requirement” is here. Do what your teacher wants.
However, note that readInput() and writeOutput() are methods and not Strings (as you currently have in code).

• The second program is to be named “MegaballTest.java” and will be
  responsible for creating a Megaball
  object and calling the writeOutput()
  and readInput() methods from the
  Megaball class.

Happy coding.

Note: The above merely describes how to “load” a Megaball number sequence into an ArrayList<Integer>. I would make a constructor which turns the number sequence (after you “build it”) into a Megaball object itself (and thus have a Megaball be immutable. However, make sure to adjust for your teachers grading habits. Perhaps the above methods could be in a MegaballBuilder, if it earns some bonus points 😉