Question

4. Modify the program geometryDemo to use the class basicGeometry and the threeSides code.

1. Note from the comments in the main routine that it wants an input argument of 3 to solve for a triangle and 4 to solve for a square or rectangle.
2. MODIFY the code to add another method in the 'threeSides' and 'fourSides' classes to return the perimeter. ASSUME the following for TRIANGLES.
   ** for AREA (1/2 * base * height) dimension1 is base, dimension2 is height
   ** for Volume (1/2 * base * height * depth or altitude) dimension1 is base, dimension2 is height and dimension3 is altitude
   ** for Perimeter, the 3 dimensions are the 3 sides.

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geometryDemo Code

package com.java24hours;

/**
* geometryDemo to show class inheritance
* super class 'basicGeometry' is inherited by class 'fourSides'
* class fourSides is inherited by class 'threeSides'
*
*
*/
public class geometryDemo
{
public static void main(String[] args)
{
// Create the main object. the threeSides class includes all functions, so use that
// because threeSides inherits (extends) all of the 4 sides public data and methods
threeSides myGeometry = new threeSides();
  
  
//variables for calculation outputs
double outArea = 0;
double outVolume = 0;
  
//must have a numeric argument it it will fail
if (args.length == 0)
{
System.out.println("ERROR ** numeric input argument required: must be 3 (triangle) or 4 (square/rectangle)");
return;
}
//pass in number of sides... NOTE this will still crash if input is not a number
int acount = Integer.valueOf(args[0]);

//initialize all dimensions (firstDimension, secondDimension, thirdDimension)
// This is INSTEAD of initializing the class object as you have done before
// rather than passin the values in when you create the object like
// threSides myGeometry = new threeSides(12, 20, 4);
// a method is needed to sent in the initial data...

myGeometry.setDimensions(12, 20, 4);
//initialize the 4 sided only object
geom4Sides.setDimensions(12,20,4);
//determine which methods for area and volume to call based on number of sides
switch (acount)
{
case 3:
System.out.println("Triangle calculations:");
outArea = myGeometry.getTArea();
outVolume = myGeometry.getTVolume();

//need new call here to get perimeter,
// method added to 3 sdes, getTPerimeter

break;

case 4:
System.out.println("Square/rectangle calculations:");
outArea = myGeometry.getShapeArea();
outVolume = myGeometry.getVolume();

//let's see if we get the same values using the generic myGeometry that is
//class threeSides inheriting (extending) 4 sides, or the actual 4sides class
double fsArea = geom4Sides.getShapeArea();
double fsVolume = geom4Sides.getVolume();
System.out.println("Using the fourSides class, Area=" + fsArea + " Volume=" + fsVolume);
  
//need new call here to get perimeter,
// method added to 4 sides, getPerimeter

break;

default:
System.out.println("Invalid argument count = " + acount + " Pass in 3 or 4 arguments");
}

// Display the calculated area and volume.
System.out.println("Area=" + outArea + " Volume=" + outVolume);
}
}

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basicGeometry Class Code

package com.java24hours;

public class basicGeometry
{
//length and width of initial shape; for triangle, length is height
double firstDimension;
double secondDimension;
double thirdDimension;

//initialize shape dimensions
public void setShape(double dim1, double dim2, double dim3)
{
firstDimension = dim1;
secondDimension = dim2;
thirdDimension = dim3;
}

}

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threeSides Code

//triangle calculations inherit rectangle and main geometry classes
public class threeSides extends fourSides
{
//triangles cut square/rectangle measurements in half
double inHalf = .5;

//triangle area is half of rectangle area
public double getTArea()
{
//use the inherited method for area, and cut in half for triangle
return getShapeArea() * inHalf;
}

//triangle volume first 3 dimensions multiplied, then cut in half
public double getTVolume()
{
//use the inherited method for volume, and cut in half for triangle
return (firstDimension * secondDimension * thirdDimension * inHalf);
}

//triangle perimeter... add a new method to calculate the perimeter given the 3 dimensions
// remember, since setShape was called in the beginning, you have access to the
// data from the class variables firstDimension, secondDimension,

}

Answer 1

Here is the geometryDemo class:

import java.util.*;
import java.io.*;
public class geometryDemo extends threeSides
{
        public static void main(String[] args)
        {
                threeSides myGeometry = new threeSides();
                fourSides geom4Sides=new fourSides();
                double outArea = 0;
                double outVolume = 0;
                double outPerimeter=0;
                if (args.length == 0)
                {
                        System.out.println("ERROR ** numeric input argument required: must be 3 (triangle) or 4 (square/rectangle)");
                        return;
                }
                int acount = Integer.valueOf(args[0]);
                myGeometry.setDimensions(12, 20, 4);
                geom4Sides.setDimensions(12,20,4);
                switch (acount)
                {
                case 3:
                        System.out.println("Triangle calculations:");
                        outArea = myGeometry.getTArea();
                        outVolume = myGeometry.getTVolume();
                        outPerimeter=myGeometry.getTPerimeter();        
                        break;

                case 4:
                        System.out.println("Square/rectangle calculations:");
                        outArea = myGeometry.getShapeArea();
                        outVolume = myGeometry.getVolume();
                        outPerimeter=myGeometry.getPerimeter();
                        double fsArea = geom4Sides.getShapeArea();
                        double fsVolume = geom4Sides.getVolume();
                        //double fsPerimeter=geom4Sides.getPerimeter();
                        System.out.println("Using the fourSides class, Area=" + fsArea + " Volume=" + fsVolume);
                        break;
                default:
                        System.out.println("Invalid argument count = " + acount + " Pass in 3 or 4 arguments");
                }
                System.out.println("Area=" + outArea + " Volume=" + outVolume+ " Perimeter=" + outPerimeter);
        }
}

Now,here is the basicGeometry class:

import java.util.*;
public class basicGeometry{
        double firstDimension=12;
        double secondDimension=20;
        double thirdDimension=4;
        public void setShape(double dim1,double dim2,double dim3){
                firstDimension=dim1;
                secondDimension=dim2;
                thirdDimension=dim3;
        }
}

Now,here is the threeSides class:

import java.util.*;

public class threeSides extends fourSides{
        double inHalf=.5;
        public int setDimensions(int firstDimension,int secondDimension,int threeDimension){
                firstDimension=12;
                secondDimension=20;
                threeDimension=4;
                return 0;
        }
        public double getTArea(){
                return getShapeArea()*inHalf;
        }
        public double getTVolume(){
                return (firstDimension*secondDimension*thirdDimension*inHalf);
        }
        public double getTPerimeter(){
                return (firstDimension+secondDimension+thirdDimension); 
        }
}

Now,here is the fourSides class:

import java.util.*;

public class fourSides extends basicGeometry{
        
        public int setDimensions(int firstDimension,int secondDimension,int threeDimension){
                firstDimension=12;
                secondDimension=20;
                threeDimension=4;
                return 0;
        }
        public double getShapeArea(){
                return (firstDimension*secondDimension);
        }
        public double getVolume(){
                return (firstDimension*secondDimension*thirdDimension);
        }
        public double getPerimeter(){
                return (2*firstDimension*secondDimension);
        }
}

Here is the modification of the program.

Thanks!...