Thread: Array of object

Could someone explain to me how array of object work? Like in this code below, how does the program know when to use the second shapes in the shapes array? "new ShapesV8(7, 13)"

class ShapesV8
{
    //declaration of private instance variables
    private int mySide1, mySide2;
    private double myArea, myHypoteneuse;
 
    //constructor for ojbects of type ShapesV8
    ShapesV8(int s1, int s2)
    {
        mySide1 = s1;
        mySide2 = s2;
        myArea = 0.0;
        myHypoteneuse = 0.0;
    }
 
    //mutator method to calculate the area of a triangle
    public void calcTriArea()
    {
        myArea = mySide1 * mySide2 * .5;
    }
 
    //getter method to return the value of the area of a triangle
    public double getTriArea()
    {
        return myArea;
    }
 
    //mutator method to calculate the hypoteneuse of a triangle
    public void calcHypoteneuse()
    {
        myHypoteneuse = Math.sqrt(Math.pow(mySide1, 2) + Math.pow(mySide2, 2));
    }
 
    //getter method to return the value of the hypoteneuse of a triangle
    public double getHypoteneuse()
    {
        return myHypoteneuse;
    }
 
    //getter method to return the value of side 1 of a triangle
    public int getSide1()
    {
        return mySide1;
    }
 
    //getter method to return the value of side 2 of a triangle
    public int getSide2()
    {
        return mySide2;
    }
}

public class ShapesV8Tester
{   
    public static void main(String[] args)
    {
        //declaration of variables
        int side1A, side2A, side1B, side2B; 
        double hypoteneuseA, triAreaA, hypoteneuseB, triAreaB;
 
        //initialization of array of objects
        ShapesV8[] shapes = {new ShapesV8(10, 5),
                             new ShapesV8(7, 13)};
        //call methods
        for(int index = 0; index < shapes.length; index++)
        {
            shapes[index].calcTriArea();
            shapes[index].calcHypoteneuse();
        }
 
        //print results
        System.out.println("        Side 1    Side 2     Hypoteneuse       Area");
        for(int index = 0; index < shapes.length; index++)
        {
            System.out.printf("%12d %9d %14.1f %13.1f%n", 
                      shapes[index].getSide1(), shapes[index].getSide2(), 
                      shapes[index].getHypoteneuse(), shapes[index].getTriArea());
        }
}

The elements of the array are use as int s1 and int s2 in the constructor. The program is to calculate the area of triangle. So one triangle have a side of 10 and 5 while the other triangle have a side of 7 and 13.- What I don't understand is how does the program know when to calculate the second triangle after the first. Thanks

So since there is two items in the shapes array of object, the program automatically run through both of the item?

 ShapesV8[] shapes = {new ShapesV8(10, 5),
                             new ShapesV8(7, 13)};

So just like a normal array, this array of object have .length of 4?

It say the length is 2. Does each new ShapesV8 count as one? Or each number count as one? Kind of lost here sorry. So is new ShapesV8(10, 5) one element and new ShapesV8(7, 13) another elements?

ShapesV8[] shapes = {new ShapesV8(10, 5),
                             new ShapesV8(7, 13)};