import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class NestedIf extends Applet implements ActionListener
{
    Label Prompt;
    TextField ScoreText;
    Button GradeButton;
    int Score;

    public void init()
    {
      Prompt = new Label("Enter Score");
      add(Prompt);
      ScoreText = new TextField(3);
      add(ScoreText);
      GradeButton = new Button("Show Grade");
      add(GradeButton);
      GradeButton.addActionListener(this);
    }

    public void paint(Graphics g)
    {
        if (Score>100)
            g.drawString("Invalid score - Score exceeds hundred",10,50);
        else if (Score>=90)
            g.drawString("A",10,50);
        else if (Score>=80)
            g.drawString("B",10,50);
        else if (Score>=70)
            g.drawString("C",10,50);
        else if (Score>=60)
            g.drawString("D",10,50);
        else if (Score>=0)
            g.drawString ("E",10,50);
        else
            g.drawString("Invalid score - Negative score",10,50);
    }

    public void actionPerformed(ActionEvent e)
    {
        Score = Integer.valueOf(ScoreText.getText()).intValue();
        repaint();
    }
}