《面向对象程序设计》上机编程题 附答案(修)(3)

} }

18、编写一个图形界面，通过文本框输入一个整数，将整数范围内所有素数打印出来。

import java.awt.*; import java.awt.event.*; import javax.swing.*;

public class dayin extends JFrame{ private JLabel label1; private JTextField text1; private JTextArea area1; private JButton button1;

public dayin(){

super(\打印素数\);

Container container=getContentPane(); container.setLayout(new FlowLayout());

label1=new JLabel(\请输入一个整数：\); container.add(label1); text1=new JTextField(5); container.add(text1);

button1=new JButton(\打印素数\); container.add(button1); area1=new JTextArea(8,12);

container.add(new JScrollPane(area1));

button1.addActionListener( new ActionListener(){

public void actionPerformed(ActionEvent event){ int a=Integer.parseInt(text1.getText()); String c=\;

for(int n=1;n<=a;n++){ boolean b=true; if(n!=1){

for(int i=2;i

if(b){

c=c+n+\是素数\+\; } }

area1.setText(c); } } );

area1.setEditable(false); setSize(500,200); setVisible(true); }

public static void main(String args[]){ dayin application=new dayin();

application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);} }

19、编写一个图形界面，通过单选按钮实现性别的选择，通过复选框实现个人兴趣爱好的选择，在点击“确定”按钮后，显示选择的结果。

import java.awt.*; import java.awt.event.*; import javax.swing.*;

public class sexhobby extends JFrame{

private JRadioButton malebutton,womenbutton; private ButtonGroup danxuan;

private JCheckBox basketball,football,swim; private JButton ok,exit; private JLabel sex,hobby; private JTextArea display;

public sexhobby(){

super(\性别及爱好\);

Container container=getContentPane(); container.setLayout(new FlowLayout()); sex=new JLabel(\性别：\); container.add(sex);

malebutton=new JRadioButton(\男\); womenbutton=new JRadioButton(\女\); danxuan=new ButtonGroup(); danxuan.add(malebutton); danxuan.add(womenbutton); container.add(malebutton);

container.add(womenbutton);

hobby=new JLabel(\爱好：\); container.add(hobby);

basketball=new JCheckBox(\篮球\); container.add(basketball); football=new JCheckBox(\足球\); container.add(football); swim=new JCheckBox(\游泳\); container.add(swim);

display=new JTextArea(5,12); display.setEditable(false);

container.add(new JScrollPane(display));

ok=new JButton(\); container.add(ok);

exit=new JButton(\); container.add(exit);

exit.addActionListener( new ActionListener(){

public void actionPerformed(ActionEvent event){ System.exit(0); } } );

shHandler handler=new shHandler(); ok.addActionListener(handler); setSize(400,300); setVisible(true); }

public static void main(String args[]){ sexhobby application=new sexhobby();

application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); }

private class shHandler implements ActionListener{ public void actionPerformed(ActionEvent event){ if(malebutton.isSelected()){ String a=\性别：男\+\+\爱好：\; if(basketball.isSelected())a=a+\篮球\; if(football.isSelected())a=a+\+\足球\; if(swim.isSelected())a=a+\+\游泳\;

display.setText(a); } else{

String a=\性别：女\+\+\爱好：\; if(basketball.isSelected())a=a+\篮球\; if(football.isSelected())a=a+\+\足球\; if(swim.isSelected())a=a+\+\游泳\; display.setText(a); } } } }

20、编写一个图形界面，通过“班级”下拉列表，实现用户选择后，在另一个下拉列表内，显示这个班级的5个学生的名字信息。班级对应的学生信息通过数组实现。

import java.awt.*;

import javax.swing.event.*; import javax.swing.*;

public class xlxk extends JFrame{ private JList classList,name; private String classnames[]={ \,\ };

private String class0[]={

\姓名1 \,\姓名2 \,\姓名3 \,\姓名4 \,\姓名5 \ };

private String class1[]={ \王一\,\李一\,\张一\,\刘一\,\赵一\ };

private String class2[]={ \王二\,\李二\,\张二\,\刘二\,\赵二\ };

Container container; public xlxk(){

super(\班级&姓名\);

container=getContentPane();

container.setLayout(new FlowLayout()); classList=new JList(classnames); classList.setVisibleRowCount(3);

classList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); container.add(new JLabel(\请选择班级：\)); container.add(new JScrollPane(classList));

container.add(new JLabel(\成员：\)); name=new JList(class0); name.setVisibleRowCount(3);

name.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); container.add(new JScrollPane(name));

classList.addListSelectionListener( new ListSelectionListener(){

public void valueChanged(ListSelectionEvent event){ if(classList.getSelectedValue()==classnames[0]) name.setListData(class1);

if(classList.getSelectedValue()==classnames[1]) name.setListData(class2); }});

setSize(400,200); setVisible(true); }

public static void main(String args[]){ xlxk application=new xlxk();

application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } }