自考Java语言程序设计课后习题代码大全

import java.applet.*; import javax.swing.*; import java.awt.*; import java.awt.event.*; class MyWindow extends JFrame implements ActionListener{ JButton button1,button2; static JTextField text1,text2; MyWindow(String s){ super(s); Container con=this.getContentPane(); con.setLayout(new GridLayout(2,2)); button1=new JButton("求圆面积"); button2=new JButton("求三角形面积"); button1.addActionListener(this); button2.addActionListener(this); text1=new JTextField(20); text2=new JTextField(20); con.add(button1);con.add(text1); con.add(button2);con.add(text2); this.setVisible(true); this.pack(); } public static void returnCircleArea(String s){ text1.setText("圆的面积是:"+s); } public static void returnTriangleArea(String s){ text2.setText("三角形的面积是:"+s); } public void actionPerformed(ActionEvent e){ if(e.getSource()==button1){ CircleDlg dlg; dlg=new CircleDlg(this,"圆"); dlg.setVisible(true); } else if(e.getSource()==button2){ TriangleDlg dlg; dlg=new TriangleDlg(this,"三角形"); dlg.setVisible(true); } } } class CircleDlg extends JDialog implements ActionListener{ JLabel label; JTextField text; JButton Cal; CircleDlg(JFrame F,String s){ super(F,s,true); Container con=this.getContentPane(); label=new JLabel("请输入半径:"); text=new JTextField(10);text.setEditable(true); con.setLayout(new FlowLayout()); setModal(true); Cal=new JButton("计算"); Cal.addActionListener(this); con.add(label); con.add(text); con.add(Cal); con.setVisible(true);this.pack(); } public void actionPerformed(ActionEvent e){ double r,s; r=Double.parseDouble(text.getText()); s=Math.PI*r*r; MyWindow.returnCircleArea(s+""); this.setVisible(false); this.dispose(); } } class TriangleDlg extends JDialog implements ActionListener{ JLabel labela,labelb,labelc; JTextField texta,textb,textc; JButton cal; TriangleDlg(JFrame F,String s){ super(F,s,true); Container con=this.getContentPane(); con.setLayout(new GridLayout(4,2)); labela=new JLabel("请输入边长a:"); labelb=new JLabel("请输入边长b:"); labelc=new JLabel("请输入边长c:"); texta=new JTextField(10);texta.setEditable(true); textb=new JTextField(10);textb.setEditable(true); textc=new JTextField(10);textc.setEditable(true); cal=new JButton("计算"); cal.addActionListener(this); con.add(labela);con.add(texta); con.add(labelb);con.add(textb); con.add(labelc);con.add(textc); con.add(cal); con.setVisible(true);this.pack(); } public void actionPerformed(ActionEvent e){ double a,b,c,l,s; a=Double.parseDouble(texta.getText()); b=Double.parseDouble(textb.getText()); c=Double.parseDouble(textc.getText()); l=(a+b+c)/2; s=Math.sqrt(l*(l-a)*(l-b)*(l-c)); MyWindow.returnTriangleArea(s+""); this.setVisible(false); this.dispose(); } } public class ex0607 extends Applet{ MyWindow window; public void init(){ window=new MyWindow("练习0607"); } }