A general question

[wizar]

Can anyone explain to me how to use arrays between multiple classes?

Suppose I have two double arrays. I want to pass both arrays into a class where I can use the elements of both arrays in calculations (like multiplying the first element of array 1 by the first element of array 2; 2nd element of array 1 by 2nd element of array 2, etc.) Once I put these results into a third array, how would I bring it back into the first class to print it out?

If anyone could give me an example, or help me figure one out, that would be great.
Please be understanding of me. I'm a beginner, and all of you were in a similar position at one point or another. :)

[gcalvin]

package org.javaforums.arraymultiplier;

public class MyProgram {
    public static void main(String[] args) {
        double[] dArray1 = {2.4, 6.8, 5.7};
        double[] dArray2 = {7.3, 7.2, 9.56, 8.4};
        ArrayMultiplier am = new ArrayMultiplier();
        double[] result = am.multiply(dArray1, dArray2);
        for (int i = 0; i < result.length; i++) {
            System.out.println("result[" + i + "] = " + result[i] + ".");
        }
    }
}

package org.javaforums.arraymultiplier;

public class ArrayMultiplier {
    public double[] multiply(double[] d1, double[] d2) {
        int max = 0;
        int min = 0;
        if (d1.length > d2.length) {
            max = d1.length;
            min = d2.length;
        } else {
            max = d2.length;
            min = d1.length; 
        }
        double[] result = new double[max];
        for (int i = 0; i < min; i++) {
            result[i] = d1[i] * d2[i];
        }
        for (int i = min; i < max; i++) {
            if (d1.length > min) {
                result[i] = d1[i];
            } else {
                result[i] = d2[i];
            }
        }
        return result;
    }
}

Is that what you meant?

-Gary-

[sunde887]

edited: gcalvin supplied a better response before me.

[gcalvin]

Please note that my example is meant only to illustrate passing and returning array type arguments. It is not meant to imply anything about correctly multiplying arrays.

-Gary-

[wizar]

sunde, thanks for your reply. I'm sure that your solution would have helped as well, I like learning various ways to go around a problem. :)

Gary, thanks for your example, but I'm a bit confused regarding your second reply. Do you mean that the calculations using arrays should be done differently? I would have done calculations using a loop like you did, is that wrong?

[gcalvin]

sunde, thanks for your reply. I'm sure that your solution would have helped as well, I like learning various ways to go around a problem. :)

Gary, thanks for your example, but I'm a bit confused regarding your second reply. Do you mean that the calculations using arrays should be done differently? I would have done calculations using a loop like you did, is that wrong?

I'm not saying it's wrong, but I'm not saying it's right either. That's your call. Especially regarding my method of dealing with different-sized arrays -- I'm just not vouching for the "correctness" of that in any mathematical sense.

-Gary-

[wizar]

Ok, thanks. :)
Since the arrays I'm dealing with are all the same size, I guess that it's not too much of a problem.