import java.awt.geom.*;
import java.util.ArrayList;
import gpdraw.*;
public class IrregularPolygonAZ
{
    private ArrayList <Point2D.Double> myPolygon;
    private DrawingTool myPencil;
    private SketchPad myPaper;
    /**
     * Constructor for objects of class IrregularPolygonAZ
     */
    public IrregularPolygonAZ()
    {
        myPolygon = new ArrayList <Point2D.Double> ();
        myPaper = new SketchPad(500, 500);
        myPencil = new DrawingTool(myPaper);
    }

    public void add(Point2D.Double aPoint)
    {
        myPolygon.add(aPoint);
    }

    public void draw()
    {
        myPencil.up();
        myPencil.move(myPolygon.get(0).x, myPolygon.get(0).y );
        myPencil.down();
        for(int x = 1; x < myPolygon.size(); x++)
        {
            myPencil.move(myPolygon.get(x).x, myPolygon.get(x).y);
        }
        myPencil.move(myPolygon.get(0).x, myPolygon.get(0).y);
    }

    public double perimeter()
    {
        double total = 0;
        int cnt;
        for(cnt = 0; cnt < myPolygon.size() - 1; cnt++)
        {
            total += Math.sqrt(  Math.pow((myPolygon.get(cnt + 1).x - myPolygon.get(cnt).x), 2) +  Math.pow((myPolygon.get(cnt + 1).y - myPolygon.get(cnt).y), 2));
        }
        total += Math.sqrt(  Math.pow((myPolygon.get(0).x - myPolygon.get(cnt).x), 2) +  Math.pow((myPolygon.get(0).y - myPolygon.get(cnt).y), 2));
        return total;
    }

    public double area()
    {
        double total = 0;
        for(int ct = 0; ct < myPolygon.size() - 1; ct++)
        {
            total += ( (myPolygon.get(ct).x * myPolygon.get(ct+1).y) - (myPolygon.get(ct).y * myPolygon.get(ct+1).x) );
        }
        total = total / 2.0;
        return total;
    }

    public double distance(int c, int v)
    {
        double value = 0.0;
        value = Math.sqrt( Math.pow((myPolygon.get(v).x - myPolygon.get(c).x), 2) +  Math.pow((myPolygon.get(v).y - myPolygon.get(c).y), 2));
        return value;
    }
}