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("计算"); 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(resulttext1, new XYConstraints(120, 178, 120, -1)); this.add(resulttext2, new XYConstraints(120, 218, 120, -1)); this.add(label5, new XYConstraints(70, 218, 46, 27)); this.add(label4, new XYConstraints(70, 178, 46, 28)); this.add(label1, new XYConstraints(100, 40, -1, -1)); this.add(label2, new XYConstraints(100, 70, -1, -1)); } /**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; 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) sqrt = getsqrt(a1,b1,c1); resulttext1.setText(String.valueOf((-1)*b1/(2*a1))+"+"+String.valueOf(sqrt/(2*a1),4)+"i"); resulttext2.setText(String.valueOf((-1)*b1/(2*a1))+"-"+String.valueOf(sqrt/(2*a1),4)+"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; } }
