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Downloadable version: ShapeTest.java
 
//*******************************************************************
//
//   File:    ShapeTest.java
//   Subject: CS-112 AS5 Solutions
//   Date:    April 09, 2001
//   Author:  Gabriel Loh
//   Classes: ShapeTest
//            Shape
//            Point (from Shape)
//            Circle (from Point)
//            Square (from Point)
//            Cylinder (from Circle)
//
//*******************************************************************

//===================================================================
// CLASS ShapeTest creates a few different shapes and then prints
// out all of their names and attributes.
//===================================================================

public class ShapeTest
{
  public static void main(String args[])
  {
    Shape[] shapes = new Shape[6];
        
    shapes[0] = new Point (7, 11);
    shapes[1] = new Circle (22, 8, 3.5);
    shapes[2] = new Square (5, 8, 7.0);
    shapes[3] = new Cylinder (10, 10, 3.3, 10);
    shapes[4] = new Point (10, 4);
    shapes[5] = new Cylinder (5, 7, 8.3, 5);
    
    for (int i = 0; i < 6; i++)
    {
      System.out.print ((shapes[i]).name());
      System.out.print (": ");
      shapes[i].print();
      System.out.println ("\nArea = " + (Math.round(shapes[i].area())));
      System.out.println ("Volume = " + (Math.round(shapes[i].volume())) + "\n");
    }
  }  // end of main
}  // end of ShapeTest


//===================================================================
// CLASS Shape is the root of our general hierarchy of shapes.
// All shapes have these four methods (area,volume,name and print).
//===================================================================

abstract class Shape
{
  // area is zero by default if not overridden by a subclass
  public double area()
  {
    return 0.0;
  }

  // volume is zero by default if not overridden by a subclass
  public double volume()
  {
    return 0.0;
  }

  // non-abstract subclasses must define a name method, which
  // returns the name of the class
  public abstract String name();

  // non-abstract subclasses must define a print method, which
  // prints out the class' attributes.
  public abstract void print();

}  // end of Shape


//===================================================================
// CLASS Point is a degenerate "shape", consisting of only a
// pair of coordinates.
//===================================================================

class Point extends Shape
{
  protected double x, y;

  public Point(double new_x, double new_y)
  {
    setPoint(new_x,new_y);
  }

  public void setPoint(double new_x, double new_y)
  {
    x = new_x;
    y = new_y;
  }

  public double getX()
  {
    return x;
  }

  public double getY()
  {
    return y;
  }

  public String name()
  {
    return "Point";
  }

  // print out the coordinates in "[x, y]" format
  public void print()
  {
    System.out.print("["+getX()+", "+getY()+"]");
  }

}  // end of Point


//===================================================================
// CLASS Circle uses Point to define the center of the circle, and
// also has a separate variable for the radius.
//===================================================================

class Circle extends Point
{
  protected double radius;

  public Circle(double new_x, double new_y, double new_radius)
  {
    super(new_x,new_y); // the Point is the center of the Circle
    setRadius(new_radius);
  }

  public void setRadius(double new_radius)
  {
    radius = new_radius;
  }

  public double getRadius()
  {
    return radius;
  }

  // use grade-school pi*r^2 formula for the area
  public double area()
  {
    // I assigned the value of getRadius() to a temporary variable
    // instead of doing getRadius()*getRadius() to avoid calling
    // the same method twice.  We're not particularly concerned
    // about performance in this class, so don't worry too much
    // about this.
    double currentRadius = getRadius();

    // 3.14 instead of Math.PI is fine for this assignment
    return Math.PI * currentRadius * currentRadius;
  }

  public String name()
  {
    return "Circle";
  }

  // print out circle info in "Center=[x, y]; Radius=r" format, using
  // superclass' print() to print out the center coords.
  public void print()
  {
    System.out.print("Center=");
    super.print();
    System.out.print("; Radius="+getRadius());
  }

}  // end of Circle


//===================================================================
// CLASS Square uses Point to define the start of the square (I
// assume would be one of the corners, but which corner is not
// important for this assignment).  A separate variable for the
// side length of the square is also maintained.
//===================================================================

class Square extends Point
{
  protected double length;

  public Square(double new_x, double new_y, double new_length)
  {
    super(new_x,new_y);  // the Point is the start of the square
    setLength(new_length);
  }

  public void setLength(double new_length)
  {
    length = new_length;
  }

  public double getLength()
  {
    return length;
  }

  // square's area is its side squared
  public double area()
  {
    double currentLength = getLength();
    return currentLength * currentLength;
  }

  public String name()
  {
    return "Square";
  }

  // print out square info in "Start=[x, y]; Length=l" format, using
  // superclass' print() to print out the start coords.
  public void print()
  {
    System.out.print("Start=");
    super.print();
    System.out.print("; Length="+getLength());
  }

}  // end of Square


//===================================================================
// CLASS Cylinder uses Circle to define the top/bottom of the
// cylinder, plus another variable height to store the height of
// the shape.
//===================================================================

class Cylinder extends Circle
{
  protected double height;

  public Cylinder(double new_x, double new_y, double new_radius, double new_height)
  {
    super(new_x,new_y,new_radius);  // the Circle defines the top/bottom of the Cylinder
    setHeight(new_height);
  }

  public void setHeight(double new_height)
  {
    height = new_height;
  }

  public double getHeight()
  {
    return height;
  }

  // surface area = 2*endArea + sidewall
  // end area = circle's area (uses super.area())
  // sidewall = circumference * height = (2*pi*r)*h
  public double area()
  {
    // endArea is the area of the two ends of the cylinder
    double endArea = 2*super.area();

    // total area is equal to the sum of the ends + the sidewall (circumference * height)
    return endArea + 2*Math.PI*getRadius()*getHeight();
  }

  // cylinder's volume is its end area (top or bottom) times its height.
  public double volume()
  {
    return super.area() * getHeight();
  }

  public String name()
  {
    return "Cylinder";
  }

  // print out circle info in "Center=[x, y]; Radius=r; Height = h" format, using
  // superclass' print() to print out the center and radius info
  public void print()
  {
    super.print();
    System.out.print("; Height="+getHeight());
  }

}  // end of Cylinder