COP3337
Section U05
Spring 2017


                              THE SOLID INTERFACE
                              ===================



I. The interface

package fall2011cop3337solids;

// describes a solid
public interface Solid 
{
    double area();
    double volume();
    
}

II. The Cube class

package fall2011cop3337solids;

// describes a cube
public class Cube implements Solid
{
    // the fields
    private double side;
    
    // s is the side
    public Cube(double s)
    {
        side = s;
    }         
    
    // get the side
    public double getSide()
    {
        return side;
        
    }        
    
    // return the area
    public double area()
    {
        return 6 * side *side;
    }        
    
    // return the volume
    public double volume()
    {
        return side * side * side;
    }        
}

III. The Sphere class

package fall2011cop3337solids;

//
public class Sphere implements Solid
{
    // the field
    private double rad; // the radius
    
    // the constructor
    // r is the radius
    public Sphere(double r)
    {
        rad = r;
    }        
    
    // return the radius
    public double getRadius()
    {
        return rad;
    }        
    
    // return the area
    public double area()
    {
        return 4.0 * Math.PI * rad * rad ;
    }        
    
    // return the volume
    public double volume()
    {
        return  4 * Math.PI * rad * rad * rad / 3; 
    }        
}

IV. The Cylinder class

package fall2011cop3337solids;

// the Cylinder solid
public class Cylinder implements Solid 
{
    // the fields
    private double rad;
    private double height; // th height
    
    // the constructor
    // r is the radius, h the height
    public Cylinder(double r, double h)
    {
        rad = r;
        height = h;
    }        
    
    // get the radius
    public double getRadius()
    {
        return rad;
    }        
    
    // return the height
    public double getHeight()
    {
        return height;
    }        
    
    // return the area
    public double area()
    {
        return 2 * Math.PI * rad * ( height + rad);
    }        
    
    // return the volume
    public double volume()
    {
        return Math.PI * rad * rad * height;
    }        
}

V. The driver


package fall2011cop3337solids;


// test solids
public class Fall2011cop3337solids {

    // adriver for solids
    public static void main(String[] args) 
    {
        // print the titles
        System.out.println("Testing Solids");
        System.out.println("==============\n\n");
        
        System.out.println("We form 6 solids.");
        Solid[] shapes = new Solid[6];
        shapes[0] = new Sphere(10);
        shapes[1] = new Cube(10);
        shapes[2] = new Cylinder(5,10);
        shapes[3] = new Cube(15);
        shapes[4] = new Cylinder(10,5);
        shapes[5] = new Sphere(12);
        
        System.out.println("The solids are:");
        print(shapes);
    }
    
    // print an array of solids
    public static void print(Solid[] arr)
    {
        // check if the array is empty
        if (arr == null || arr.length == 0)
        {
            System.out.println("The array is empty.");
            return;
        }    
        // print the array
        for (int i = 0; i < arr.length; i++ )
        {
            // print arr[i]
            if (arr[i] instanceof Sphere)
            {
                Sphere s = (Sphere) arr[i];
                System.out.println("\nThe solid is a sphere with radius "
                        + s.getRadius() + ".");
                System.out.println("The area is " + arr[i].area() + ", the volume "
                        + arr[i].volume() + ".");
            }    
            else if (arr[i] instanceof Cylinder)
            {
                Cylinder c = (Cylinder) arr[i];
                System.out.println("\nThe object is a cylinder with radius "
                        + c.getRadius() + " and height " + c.getHeight() + ".");
                System.out.println("The area is " + arr[i].area() + ", the volume "
                        + arr[i].volume() + ".");
            }      
                
            else if (arr[i] instanceof Cube)
            {
                Cube c = (Cube) arr[i];
                System.out.println("\nThe solid is a cube with side "
                        + c.getSide() + ".");
                System.out.println("The area is " + arr[i].area() + ", the volume "
                        + arr[i].volume() + ".");
            }    
            
            else
                System.out.println("\nUnknown solid.");
        }    
    }        
}


VI. The output

run:
Testing Solids
==============


We form 6 solids.
The solids are:

The solid is a sphere with radius 10.0.
The area is 1256.6370614359173, the volume 4188.790204786391.

The solid is a cube with side 10.0.
The area is 600.0, the volume 1000.0.

The object is a cylinder with radius 5.0 and height 10.0.
The area is 471.23889803846896, the volume 785.3981633974483.

The solid is a cube with side 15.0.
The area is 1350.0, the volume 3375.0.

The object is a cylinder with radius 10.0 and height 5.0.
The area is 942.4777960769379, the volume 1570.7963267948967.

The solid is a sphere with radius 12.0.
The area is 1809.5573684677208, the volume 7238.229473870883.
BUILD SUCCESSFUL (total time: 0 seconds)