import javax.microedition.lcdui.*;
public class d1 extends Form implements CommandListener
{
    TextField tf = new TextField("a", "", 500, 2);
    TextField tf1 = new TextField("b", "", 500, 2);
    Command back = new Command("trở lại", 7, 1);
    Command cong = new Command("cộng", 4, 1);
    double a = Double.parseDouble(tf.getString());
    double b = Double.parseDouble(tf1.getString());
    double c;
    public d1(midlet md)
    {
        super("phép tính");
        append(tf);
        append(tf1);
        addCommand(back);
        addCommand(cong);
        setCommandListener(md);
    }
    public void phepcong()
    {
        c = a + b;
        append("kết quả là " + c);
    }
    public void commandAction(Command cm, Displayable dp)
    {
    }
}