CODEWITHSUNDEEP
java
fdamico
fdamico

Reputation: 3

How to sum up similar variables after several new class() have been generated

Say you define a simple class

public class Box {
double width;
}

and then in Main you have multiple new classes like

Box mybox1 = new Box();
mybox1.width = x
Box mybox2 = new Box();
mybox2.width = y

and after n times

Box myboxn = new Box()
myboxn.width = n

Is there a way to sum up all the *.width with an instruction like:

for each .width
total = total + next.box.width?

Thanks!

Upvotes: 0

Views: 159

Answers (2)

Rishi Latchmepersad
Rishi Latchmepersad

Reputation: 684

I'm thinking of using a List to hold all of the widths, then summing them in a for each loop:

List<Double> widths=new ArrayList<>();

//declare all your new classes in Main and add their widths to the list
Box mybox1 = new Box();
widths.add(mybox1.width);
Box mybox2 = new Box();
widths.add(mybox2.width);

//then sum the widths
double totalWidth;
for(Double tempWidth:widths)
    totalWidth+=tempWidth;

Upvotes: 2

Jon Sampson
Jon Sampson

Reputation: 1551

Create a Collection of type Box and add each box to it as you go. Then you can simply use a for loop.

public class Box {
    int width;
    public Box(int width) {
        this.width = width;
    }

    public int getWidth() {
        return this.width;
    }
}

...

public static void main(String args[]) {
    Collection<Box> boxes = new ArrayList<Box>();
    boxes.add(new Box(1));
    boxes.add(new Box(2));
    boxes.add(new Box(3));
    boxes.add(new Box(4));

    int total = 0;
    for(Box box : boxes) {
        total = total + box.getWidth();
    }
    System.out.println("Total widths: " + total);
}

Upvotes: 2

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