Java Reference
In-Depth Information
You will be creating two source files. In a moment you will create the file
CreateSpheres.java
, which
contains the definition of the
CreateSpheres
class that has the method
main()
defined as a static method.
As usual, this is where execution of the program starts. The other file is the
Sphere.java
file, which con-
tains the definition of the
Sphere
class that you have been assembling. The
Sphere
class definition should
look like this:
class Sphere {
static final double PI = 3.14; // Class variable that has a fixed value
static int count = 0; // Class variable to count objects
// Instance variables
double radius; // Radius of a sphere
double xCenter; // 3D coordinates
double yCenter; // of the center
double zCenter; // of a sphere
// Class constructor
Sphere(double theRadius, double x, double y, double z) {
radius = theRadius; // Set the radius
// Set the coordinates of the center
xCenter = x;
yCenter = y;
zCenter = z;
++count; // Update object count
}
// Static method to report the number of objects created
static int getCount() {
return count; // Return current object count
}
// Instance method to calculate volume
double volume() {
return 4.0/3.0*PI*radius*radius*radius;
}
}
Directory "CreateSpheres"
Both files need to be in the same directory or folder — I suggest you name the directory
Create
Spheres
. Then copy or move the latest version of
Sphere.java
to this directory.
TRY IT OUT: Using the Sphere Class
Enter the following code for the file
CreateSpheres.java
and place it in the
Create Spheres
directory:
