Hi math01-ga,
I have provided the required Java code below. To compile and run
this code, you will need the Java2 SDK. You can download the Java SDK
from :
- Download : Java(TM) 2 SDK, Standard Edition, v 1_4_0_03
( http://java.sun.com/j2se/1.4/download.html )
A free Java IDE (if you need one) can be found at :
- The RealJ Java IDE
( http://www.realj.com )
The code provided below has been tested with RealJ and JDK 1.4
Copy this code into a file called TestShape.java, and then compile it.
The code contains the following classes :
- Point : This class stores the x,y coordinates of a point
- Shape : Abstract class from which the other classes inherit
- Triangle : contains methods to calculate Perimeter and the
shortest/longest side of a triangle.
- RightTriangle : Inherits from Triangle, specific to Right triangles
- EquilateralTriangle : Inherits from Triangle, overrides its methods
to optimize them for an equilateral triangle
- TestShape : contains the main function. Creates an instance of the
Triangle, RightTriangle and EquilateralTriangle classes and prints out
the output from their methods.
*********** Code from TestShape.java *************
import java.lang.Math;
import java.io.*;
// Utility Class Point
// Stores x,y coordinates of a point
class Point
{
private int x,y;
// Constructor
public Point( int newX, int newY )
{
// initialize x and y
x = newX;
y = newY;
}
// Returns value of the X coordinate
public int X()
{
return x;
}
// Returns value of the Y coordinate
public int Y()
{
return y;
}
// Utility Function
// Calculates the linear distance between
// this point and the given point pt.
// Used in Triangle to calculate length of sides
public double DistanceBetween(Point pt)
{
double distance,xd,yd;
xd = x - pt.X();
yd = y - pt.Y();
distance = Math.sqrt( xd*xd + yd*yd );
return distance;
}
} // End of Point class
//============================================
// Shape Class
// Abstract class from which other shapes inherit
abstract class Shape
{
// All shapes have a perimeter, so define abstract method
// returns a double that is the perimeter of the shape
abstract double Perimeter();
}
//===================================================
// Triangle class, inherits from abstract Shape class
// Has child classes : RightTriangle and EquilateralTriangle
class Triangle extends Shape
{
protected Point vertexA, vertexB, vertexC;
// Length of the 3 sides
protected double sideAB, sideBC, sideAC;
public Triangle()
{
sideAB = sideBC = sideAC = 0;
}
// Constructor : Takes 3 vertices, calculates sides
public Triangle (Point newA, Point newB, Point newC)
{
vertexA = newA;
vertexB = newB;
vertexC = newC;
sideAB = vertexA.DistanceBetween(vertexB);
sideBC = vertexB.DistanceBetween(vertexC);
sideAC = vertexA.DistanceBetween(vertexC);
}
// calculates and returns perimeter of this triangle
public double Perimeter()
{
return (sideAB + sideBC + sideAC);
}
// calculates and returns the length of
// the longest side of this triangle
public double LongestSide()
{
return (sideAB > sideBC ? ( sideAB > sideAC ? sideAB : sideAC) :
(sideBC>sideAC ? sideBC : sideAC) );
}
//calculates and returns the length of
//the shortest side of this triangle
public double ShortestSide()
{
if ( sideAB < sideBC )
if( sideAB < sideAC)
return sideAB;
else
return sideAC;
else
if( sideBC < sideAC )
return sideBC;
else
return sideAC;
}
// OverRide toString() to display the vertices of the triangle
public String toString()
{
return " Triangle Vertices : "
+ "A(" + vertexA.X() + "," + vertexA.Y() + "), "
+ "B(" + vertexB.X() + "," + vertexB.Y() + "), "
+ "C(" + vertexC.X() + "," + vertexC.Y() + ").";
}
} // End of Triangle class
//=============================
class RightTriangle extends Triangle
{
// Constructor
public RightTriangle(Point newA, Point newB, Point newC)
{
// assume triangle is A |\
// | \
// B |__\ C
// thats is : AB = perpendicular
// BC = base
// AC = hypotenuse
// We just call the Triangle class constructor
super ( newA, newB, newC );
}
// The Perimeter will be calculated the same as superclass
Triangle
// So we will not override the Perimeter method of the Triangle
class
// In a right triangle, the longest side will always be the
hypotenuse
public double LongestSide()
{
// return hypotenuse
return sideAC;
}
// In a right triangle, hypotenuse >= other two sides
// So we just compare base and the perpendicular
// and return the shortest one
public double ShortestSide()
{
return ( sideAB < sideBC ? sideAB : sideBC );
}
} // End of the RightTriangle class
//=========================================
class EquilateralTriangle extends Triangle
{
public EquilateralTriangle(Point newA, Point newB, Point newC )
{
vertexA = newA;
vertexB = newB;
vertexC = newC;
// Need to calculate only one side
// since all sides have same length
sideAB = vertexA.DistanceBetween(vertexB);
sideBC = sideAB;
sideAC = sideAB;
}
// Perimeter = 3 * length of any side
public double Perimeter()
{
return 3 * sideAB;
}
// Longest side = any side ( since all sides have same length)
public double LongestSide()
{
return sideAB;
}
// Shortest side = any side ( since all sides have same length)
public double ShortestSide()
{
return sideAB;
}
} // End Of EquilateralTriangle class
//==========================================
public class TestShape
{
public static void main (String [] args)
{
Point A = new Point(1,4);
Point B = new Point(2,0);
Point C = new Point(5,2);
Triangle tri = new Triangle(A,B,C);
System.out.print("Created New Triangle Object.\n" + tri);
System.out.println("\n Perimeter = " + tri.Perimeter() );
System.out.println(" Longest Side = " + tri.LongestSide() );
System.out.println(" Shortest Side = " + tri.ShortestSide() );
// Test RightTriangle class
A = new Point(1,4);
B = new Point(0,0);
C = new Point(7,0);
RightTriangle rtTri = new RightTriangle(A,B,C);
System.out.print("Created New RightTriangle Object.\n" + rtTri);
System.out.println("\n Perimeter = " + rtTri.Perimeter() );
System.out.println(" Longest Side = " + rtTri.LongestSide() );
System.out.println(" Shortest Side = " + rtTri.ShortestSide() );
// Test EquilateralTriangle class
A = new Point(0,1);
B = new Point(0,0);
C = new Point(1,0);
EquilateralTriangle eqTri = new EquilateralTriangle(A,B,C);
System.out.print("Created New EquilateralTriangle Object.\n" +
eqTri);
System.out.println("\n Perimeter = " + eqTri.Perimeter() );
System.out.println(" Longest Side = " + eqTri.LongestSide() );
System.out.println(" Shortest Side = " + eqTri.ShortestSide() );
}
}
*********** End of TestShape.java ****************
Please note that in the constructor of the RightTriangle class, I
have made the assumption that the side AC is the Hypotenuse. This
assumption was necessary because I needed the hypotenuse values in
order to optimize the LongestSide() and the ShortestSide() methods.
Without this assumption, the RightTriangle class would have been
exactly the same as the Triangle class.
If there are any aspects of the above program that you want
modified, then please do not hesitate to ask me. I will be glad to
modify it to suit your needs. Please note that the code, as it stands
right now, completely satisfies your question.
Please do not rate this answer until it has been answered to your
satisfaction. I will be glad to make any changes you want to the
program, until you are satisfied.
If you need any clarifications, just ask!
Regards,
Theta-ga
:-)
=============================================
Google Search Terms Used :
download Java SDK
java default access private public
java override tostring |
Clarification of Answer by
theta-ga
on
29 Jan 2003 06:35 PST
Hi math01-ga,
To keep compilation simple, all of the code provided above is
contained in a single file. Here are the steps you need to take to
compile the above program:
- Create an empty file TestShape.java
- Copy the Java code provided and paste it into TestShape.java
- Make the changes to the code, as noted in my earlier
clarification.
- Save the file TestShape.java
- To compile the file, use the following command:
javac TestShape.java
This assumes that your javac.exe and TestShape.java are both in
your search path. If you get a file not found error, provide the full
path to the files.
- After compilation, a separate class file will be created for
each of the classes in TestShape.java
- To run the program, give the command :
java TestShape
Please note that TestShape is not followed by any file
extension.
************
If you so want, you can move each class to its own separate file. In
this case, when you compile the file containing the TestShape class,
the compiler will detect that it needs to compile the other classes
and will do so automatically. Just make sure that you name the Java
file with the class name.(For eg: Point.java, Triangle.java,
TestShape.java etc). The remaining instructions will remain the same.
If you have any problems, contact me. :-)
************
Hope this helps.
For more instructions, check out :
- How to compile a Java program
( http://csgrad.cs.vt.edu/~vanmetre/work/cs5204/htcajp.html
)
- Notes on Java
( http://web.cs.mun.ca/courses/cs3710-w98/java/ )
If you need any clarifications, just ask!
Regards,
Theta-ga
|
Request for Answer Clarification by
math01-ga
on
10 Feb 2003 03:28 PST
Hi theta-ga,
I was just wondering if you can help me out with this program. I have
tried to compiled and run this gui program but nothing happened (no
activity on screen just the dos box). Below is the program.
Thanks
import java.awt.*;
import javax.swing.*;
public class NewGUI extends JApplet {
// set up row 1
JPanel row1 = new JPanel();
JLabel ptLabel = new JLabel("Choose: ");
JComboBox playType = new JComboBox();
// set up row 2
JPanel row2 = new JPanel();
JLabel numbersLabel = new JLabel("Your picks: ", JLabel.RIGHT);
JTextField[] numbers = new JTextField[6];
JLabel winnersLabel = new JLabel("Winners: ", JLabel.RIGHT);
JTextField[] winners = new JTextField[6];
// set up row 3
JPanel row3 = new JPanel();
ButtonGroup option = new ButtonGroup();
JCheckBox stop = new JCheckBox("Stop", true);
JCheckBox play = new JCheckBox("Play", false);
JCheckBox reset = new JCheckBox("Reset", false);
// set up row 4
JPanel row4 = new JPanel();
JLabel got3Label = new JLabel("3 of 6: ", JLabel.RIGHT);
JTextField got3 = new JTextField();
JLabel got4Label = new JLabel("4 of 6: ", JLabel.RIGHT);
JTextField got4 = new JTextField();
JLabel got5Label = new JLabel("5 of 6: ", JLabel.RIGHT);
JTextField got5 = new JTextField();
JLabel got6Label = new JLabel("6 of 6: ", JLabel.RIGHT);
JTextField got6 = new JTextField(10);
JLabel drawingsLabel = new JLabel("Drawings: ", JLabel.RIGHT);
JTextField drawings = new JTextField();
JLabel yearsLabel = new JLabel("Years: ", JLabel.RIGHT);
JTextField years = new JTextField();
public void init() {
GridLayout appletLayout = new GridLayout(5, 1, 10, 10);
Container pane = getContentPane();
pane.setLayout(appletLayout);
FlowLayout layout1 = new FlowLayout(FlowLayout.CENTER,
10, 10);
row1.setLayout(layout1);
playType.addItem("Quick Pick");
playType.addItem("Personal");
row1.add(ptLabel);
row1.add(playType);
pane.add(row1);
GridLayout layout2 = new GridLayout(2, 7, 10, 10);
row2.setLayout(layout2);
row2.setLayout(layout2);
row2.add(numbersLabel);
for (int i = 0; i < 6; i++) {
numbers[i] = new JTextField();
row2.add(numbers[i]);
}
row2.add(winnersLabel);
for (int i = 0; i < 6; i++) {
winners[i] = new JTextField();
winners[i].setEditable(false);
row2.add(winners[i]);
}
pane.add(row2);
FlowLayout layout3 = new FlowLayout(FlowLayout.CENTER,
10, 10);
option.add(stop);
option.add(play);
option.add(reset);
row3.setLayout(layout3);
row3.add(stop);
row3.add(play);
row3.add(reset);
pane.add(row3);
GridLayout layout4 = new GridLayout(2, 6, 20, 10);
row4.setLayout(layout4);
row4.add(got3Label);
got3.setEditable(false);
row4.add(got3);
row4.add(got4Label);
got4.setEditable(false);
row4.add(got4);
row4.add(got5Label);
got5.setEditable(false);
row4.add(got5);
row4.add(got6Label);
got6.setEditable(false);
row4.add(got6);
row4.add(drawingsLabel);
drawings.setEditable(false);
row4.add(drawings);
row4.add(yearsLabel);
years.setEditable(false);
row4.add(years);
pane.add(row4);
setContentPane(pane);
}
public static void main(String[] arguments) {
NewGUI ng = new NewGUI();
}
}
|
