java project

import java.awt.*;
import java.applet.*;
import java.util.*;

class Polygon
{
  double x[], //contains x coordinate for vertices
         y[], //contains y coordinate for vertices
         xc,  //(xc,yc) = figure's center or
         yc;  //reference point

  int    totalPoints; //number of vertices

  //Given method: Explain function
  Polygon()
  {
  }

  Polygon(int totalPoints, double xc, double yc)
  {
    this.totalPoints = totalPoints;
    x = new double[totalPoints];
    y = new double[totalPoints];
    this.xc = xc;
    this.yc = yc;
  }

  void setCenterCoords(double xc, double yc)
  {
    this.xc = xc;
    this.yc = yc;
  }

  void setCoordForOneVertex(int index, double x, double y)
  {
    if ((index < totalPoints)&& (index >= 0))
    {
      this.x[index] = x;
      this.y[index] = y;
    }
  }

  void grow(double factor)
  {
    int i;

    for (i = 0; i < totalPoints; i++)
    {
      x[i] = (x[i] - xc) * factor + xc;
      y[i] = (y[i] - yc) * factor + yc;
    }
  }

  //New method: TO DO
  double getPerimeter()
  {
    double perimeter = 0;
    {
      //requires the code to calculate the perimeter
    }
    return (perimeter);
  }

  void moveDown(double displacement)
  {
    for (int i = 0; i < totalPoints; i++)
    {
      y[i] = y[i] + displacement;
    }
    yc = yc + displacement;
  }

  void draw(Graphics g)
  {
    int i;
    for (i = 0; i < totalPoints - 1; i++)
    {
      g.drawLine((int)x[i],(int)y[i],(int)x[i+1],(int)y[i+1]);
    }
    g.drawLine((int)x[0],(int)y[0],(int)x[totalPoints - 1],(int)y[totalPoints - 1]);
  }
}

class Triangle extends Polygon
{
  Triangle(double x1, double y1, double x2, double y2,
           double x3, double y3, double xc, double yc)
  {
    super(3,xc,yc);
    setCoordForOneVertex(0, x1, y1);
    setCoordForOneVertex(1, x2, y2);
    setCoordForOneVertex(2, x3, y3);
  }

  //New method: TO DO
  double getArea()
  {
    double area = 0.0;
    {
      //requires code to calculate area
    }
    return (area);
  }

  //New method: TO DO
  void displayStringInside(String theString)
  {
    //requires code to display theString centralized
    //within the figure
  }
}

class Rectangle extends Polygon
{
  //New: Given constructor
  Rectangle ()
  {
    super(4,0.0,0.0);
  }

  Rectangle (double x1, double y1, double x2, double y2)
  {
    super(4,0.0,0.0);
    double midX,
           midY;

    midX = (x1 + x2)/2.0;
    midY = (y1 + y2)/2.0;
    setCenterCoords(midX,midY);
    setCoordForOneVertex(0, x1, y1);
    setCoordForOneVertex(1, x2, y1);
    setCoordForOneVertex(2, x2, y2);
    setCoordForOneVertex(3, x1, y2);
  }

  //New method: TO DO
  double getArea()
  {
    double area = 0.0;
    {
      //requires code to calculate area
    }
    return (area);
  }

  //New method: TO DO
  void displayStringInside(String theString)
  {
    //requires code to display theString centralized
    //within the figure
  }
}

//*** New class: Given and to be Explained
class Cuadrado extends Rectangle
{
  Cuadrado (double x1, double y1, double width)
  {
    super(x1,y1,x1+width,y1+width);
  }
}

public class HerenciaGeometria2 extends java.applet.Applet
{
  Polygon poly1;
  Triangle triangle1;
  Rectangle rectangle1;
  Graphics g;

  void delayMiliSecs(int delay)
  {
    try
     {
       Thread.sleep(delay);
     }
     catch(InterruptedException e)
     {
     }
  }

  public void init()
  {

    triangle1 = new Triangle(10,10,30,50,40,20,25,30);
    rectangle1 = new Rectangle(80,80,140,100);

    poly1 = new Polygon(5,40,25);
    poly1.setCoordForOneVertex(0,20,40);
    poly1.setCoordForOneVertex(1,60,40);
    poly1.setCoordForOneVertex(2,60,10);
    poly1.setCoordForOneVertex(3,20,10);
    poly1.setCoordForOneVertex(4,30,30);
    poly1.moveDown(100);

    setBackground(Color.red);
    setForeground(Color.black);
  }

  public void start()
  {
      //no code here
  }

  public void paint(Graphics g)
  {
    triangle1.draw(g);
    triangle1.moveDown(50);
    delayMiliSecs(1000);
    triangle1.draw(g);
      poly1.draw(g);
    delayMiliSecs(1000);
    poly1.grow(2);
      poly1.draw(g);
    delayMiliSecs(1000);
    rectangle1.grow(2);
    rectangle1.draw(g);
    }
}