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

public class plotStream{

	public Vector XX;
	public Vector YY;
	public Vector XXerr;
	public Vector YYerr;
	
	public plotStream(){
		XX = new Vector();
		YY = new Vector();
		XXerr = new Vector();
		YYerr = new Vector();
	}
	
	public int size(){
	 	return XX.size();
	 }
	 
	public void add(double X, double Y){
		add( X, 0.0, Y, 0.0);
	 }		

	public void add(double X, double Y, double Yerr){
		add(X, 0.0, Y, Yerr);
	 }		

	public void add(double X, double Xerr, double Y, double Yerr){
	 	XX.addElement(new Double(X));
	 	YY.addElement(new Double(Y));
	 	XXerr.addElement(new Double(Xerr));
	 	if (Yerr < 0.0)  
                   System.out.println("  The error on x should be positive.");
	 	YYerr.addElement(new Double(Yerr));
	 	if (Yerr < 0.0)  
                    System.out.println("  The error on y should be positive.");
	 }		

	public double x(int i){
		return ((Double) XX.elementAt(i)).doubleValue();
	}
	
	public double y(int i){
		return ((Double) YY.elementAt(i)).doubleValue();
	}

	public double xerr(int i){
		return ((Double) XXerr.elementAt(i)).doubleValue();
	}
	
	public double yerr(int i){
		return ((Double) YYerr.elementAt(i)).doubleValue();
	}
}