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 (Xerr < 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();
  }
}