package untitled2;import java.awt.*;import java.awt.event.*;import java.applet.*;import com.borland.jbcl.layout.*;public class ifexample extends Applet {  double result;  boolean isStandalone = false;  TextField paratext1 = new TextField();  TextField paratext2 = new TextField();  TextField paratext3 = new TextField();  Label label1 = new Label();  Label label2 = new Label();  Label label3 = new Label();  Button button1 = new Button();  TextField resulttext1 = new TextField();  XYLayout xYLayout1 = new XYLayout();  TextField resulttext2 = new TextField();  Label label4 = new Label();  Label label5 = new Label();  /**Get a parameter value*/  public String getParameter(String key, String def) {    return isStandalone ? System.getProperty(key, def) :      (getParameter(key) != null ? getParameter(key) : def);  }  /**Construct the applet*/  public ifexample() {  }  /**Initialize the applet*/  public void init() {    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  /**Component initialization*/  private void jbInit() throws Exception {    paratext1.setFont(new java.awt.Font("Dialog", 0, 16));    paratext1.setText("0");    paratext2.setFont(new java.awt.Font("Dialog", 0, 16));    paratext2.setText("0");    paratext3.setFont(new java.awt.Font("Dialog", 0, 16));    paratext3.setText("0");    label1.setFont(new java.awt.Font("Dialog", 0, 16));    label1.setText("a");    label2.setFont(new java.awt.Font("Dialog", 0, 16));    label2.setText("b");    label3.setFont(new java.awt.Font("Dialog", 0, 16));    label3.setText("c");    button1.setLabel("計(jì)算");    button1.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        button1_actionPerformed(e);      }    });    resulttext1.setEditable(false);    resulttext1.setFont(new java.awt.Font("Dialog", 0, 16));    this.setLayout(xYLayout1);    resulttext2.setEditable(false);    resulttext2.setFont(new java.awt.Font("Dialog", 0, 16));    label4.setFont(new java.awt.Font("Dialog", 0, 16));    label4.setText("x1=");    label5.setFont(new java.awt.Font("Dialog", 0, 16));    label5.setText("x2=");    this.add(paratext3,    new XYConstraints(120, 100, 70, -1));    this.add(button1,    new XYConstraints(120, 140, -1, -1));    this.add(paratext2,     new XYConstraints(120, 70, 70, -1));    this.add(paratext1,     new XYConstraints(120, 40, 70, -1));    this.add(label3,   new XYConstraints(100, 100, -1, -1));    this.add(label1,   new XYConstraints(100, 40, -1, -1));    this.add(label2,   new XYConstraints(100, 70, -1, -1));    this.add(label4, new XYConstraints(19, 178, 46, 28));    this.add(resulttext1,   new XYConstraints(69, 178, 220, -1));    this.add(resulttext2,   new XYConstraints(69, 218, 220, -1));    this.add(label5, new XYConstraints(19, 218, 46, 27));  }  /**Get Applet information*/  public String getAppletInfo() {    return "Applet Information";  }  /**Get parameter info*/  public String[][] getParameterInfo() {    return null;  }  void button1_actionPerformed(ActionEvent e) {      double a1,b1,c1;      double sqrt;      double x1,x2;      resulttext1.setText("");      resulttext2.setText("");      try{         a1 = Double.parseDouble(paratext1.getText());         b1 = Double.parseDouble(paratext2.getText());         c1 = Double.parseDouble(paratext3.getText());         if ((a1 == 0)&&(b1 != 0)){             x1 = c1/b1;             resulttext1.setText(String.valueOf(x1));         }         if (a1 != 0){            if ((b1*b1-4*a1*c1)>=0){              sqrt = getsqrt(a1,b1,c1);               x1 = ((-1)*b1+sqrt)/(2*a1);               x2 = ((-1)*b1-sqrt)/(2*a1);              resulttext1.setText(String.valueOf(x1));              resulttext2.setText(String.valueOf(x2));            }        if ((b1*b1-4*a1*c1)<0){               sqrt = getsqrt(a1,b1,c1);               resulttext1.setText(String.valueOf((-1)*b1/(2*a1))+"+"+String.valueOf(sqrt/(2*a1))+"i");               resulttext2.setText(String.valueOf((-1)*b1/(2*a1))+"-"+String.valueOf(sqrt/(2*a1))+"i");            }          }      }catch(Exception ex){}  }  public double getsqrt(double x,double y,double z){       result = Math.sqrt(Math.abs(y*y-4*x*z));       return result;   }}