Re: Sending data from one class to another

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.help

Date:

Thu, 18 Oct 2007 18:33:31 -0400

Message-ID:

<DqadnewMTaChQoranZ2dnUVZ_qygnZ2d@comcast.com>

sdlt85@gmail.com wrote:

Hi, I want to send the values that the user enters and I am storing
them in several arrays in the IntegerSetTest class. It need to be
sended to the IntergerSet class to find the union, intersection, etc.

I don't know what you're asking. Are you asking how to pass values to a
method of another class? You do it by making a method call with values in the
argument list, e.g.,

   SomeFoo foo = new SomeFoo();
   foo.someMethod( 23, 23.0, "23" );

Or, if you are passing variables,

   foo.someMethod( intValue, doubValue, anotherValue );

Here is IntegerSetTest class:

You call it "Integer" here and "Interger" later, just noticing.

import java.util.*;
public class IntegerSetTest
{
    public static void main(String args[])
    {
        Scanner input = new Scanner(System.in);
        String inputValue;

        String strArray1[] = new String[100];
        int countInts = 0;
        for(int i = 0; i < strArray1.length; i++)
        {
            System.out.println("Enter integers for set A. (Press any
other key to finish set). ");

This println() call will happen every time through the loop.

            inputValue = input.next();
            try
            {
                Integer.parseInt(inputValue);

You parse an int out of the inputValue, then you throw it away. then you
parse it again later. You could skip all that fooferol by parsing the int and
putting it right into the int array (which really shouldn't be called
"intArray", but that's another matter). This will eliminate the need for the
String array.

                strArray1[i] = inputValue;
                countInts++;
            }
            catch(NumberFormatException ex)
            {

You can use Exceptions to control logic flow like this, but it isn't recommended.

                break;
            }
        }
        int intArray1[] = new int[countInts];
        for(int i = 0; i < countInts; i++)
            intArray1[i] = Integer.parseInt(strArray1[i]);

Yep, here's that second parseInt() of the same data.

        String strArray2[] = new String[100];
        countInts = 0;
        for(int i = 0; i < strArray2.length; i++)
        {
            System.out.println("Enter integers for set B. (Press any
other key to finish set). ");
            inputValue = input.next();
            try
            {
                Integer.parseInt(inputValue);
                strArray2[i] = inputValue;
                countInts++;
            }
            catch(NumberFormatException ex)
            {
                break;
            }
        }
        int intArray2[] = new int[countInts];
        for(int i = 0; i < countInts; i++)
            intArray2[i] = Integer.parseInt(strArray2[i]);

        String strArray3[] = new String[100];
        countInts = 0;
        for(int i = 0; i < strArray3.length; i++)
        {
            System.out.println("Enter integers for set C. (Press any
other key to finish set). ");
            inputValue = input.next();
            try
            {
                Integer.parseInt(inputValue);
                strArray3[i] = inputValue;
                countInts++;
            }
            catch(NumberFormatException ex)
            {
                break;
            }
        }
        int intArray3[] = new int[countInts];
        for(int i = 0; i < countInts; i++)
            intArray3[i] = Integer.parseInt(strArray3[i]);

        String strArray4[] = new String[100];
        countInts = 0;
        for(int i = 0; i < strArray4.length; i++)
        {
            System.out.println("Enter integers for set D. (Press any
other key to finish set). ");
            inputValue = input.next();
            try
            {
                Integer.parseInt(inputValue);
                strArray4[i] = inputValue;
                countInts++;
            }
            catch(NumberFormatException ex)
            {
                break;
            }
        }
        int intArray4[] = new int[countInts];
        for(int i = 0; i < countInts; i++)
            intArray4[i] = Integer.parseInt(strArray4[i]);
}

After watching the code do the same thing four times, it should make you want
to write a method that captures that logic, and call it four times.

And here is IntergerSet class:

You really should've named it with conventional spelling.

import java.util.Scanner;

public class IntergerSet
{
private static final int SIZE = 101;
private boolean[] arraySet = new boolean[SIZE];

FYI, this array is now completely populated with 'false' values.

     private boolean validEntry(int k)
    {
        return k>=0 && k<=SIZE;
    }

    // No-arguments.
    public IntergerSet()
    {
        for(int i=0; i<SIZE; i++)
            arraySet[i] = false;

This loop, besides missing its braces ('{' and '}'), is completely
unnecessary. It is setting values to 'false' that already were 'false'.

     }

    //overloading
    public IntergerSet(int arraySet[])
    {
     //obtain the values of the set that the user enter.

Show this logic. Make sure to protect against mismatches with SIZE.

    }

    public IntergerSet union(IntergerSet other)
    {
     IntergerSet res = new IntergerSet();

     for(int i=0; i<SIZE; i++)
     res.arraySet[i] = this.arraySet[i]||other.arraySet[i];
        return res;
    }

    public IntergerSet intersection(IntergerSet other)
    {
    IntergerSet res = new IntergerSet();

        for(int i=0; i<SIZE; i++)
         res.arraySet[i] = this.arraySet[i]&&other.arraySet[i];
        return res;
    }
}

--
Lew