import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Cross extends JFrame {
    private JTextField data;
    private JButton go;
  
    public Cross(int size) {
        super("Cross Drawing Program");
        setSize(size, size);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        data = new JTextField("size of cross?");
        go = new JButton("draw it");
        go.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    makeCross(new Integer(data.getText()));
                }
            });
        Container myPane = getContentPane();
        myPane.setLayout(new FlowLayout());
        myPane.add(go);
        myPane.add(data);
        validate();
    }

    public void makeCross(int size) {
        Graphics g = getGraphics();
        int wid = getWidth();
        int ht = getHeight();
        g.drawLine(wid/2-size/2, ht/2-size/2, wid/2+size/2, ht/2+size/2);
        g.drawLine(wid/2+size/2, ht/2-size/2, wid/2-size/2, ht/2+size/2);
    }

    public static void main(String[] args) {
        new Cross(400);
    }
}