java计算机倒数代码 java倒叙输出数字

用java编写一个倒计时器代码 。import java.awt.BorderLayout;import java.awt.Container;import java.awt.Font;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JOptionPane;import javax.swing.JPanel;import javax.swing.JTextField;public class TimerDemo extends JFrame implements ActionListener {private static final long serialVersionUID = 201306211111L;private JTextField screen = new JTextField("0");private JButton start = new JButton("开始");private JButton reset = new JButton("重置");private JPanel panel = new JPanel();private boolean isRunning;private int time;private int timeBetween;public TimerDemo(int timeBetween) {super("计时器");this.timeBetween = timeBetween;try {init();} catch (Exception e) {e.printStackTrace();}}public TimerDemo() {super("计时器");this.timeBetween = 100;try {init();} catch (Exception e) {e.printStackTrace();}}private void init() {panel.setLayout(new GridLayout());panel.add(start);panel.add(reset);start.addActionListener(this);reset.addActionListener(this);screen.setFont(new Font("幼圆", Font.BOLD, 60));screen.setHorizontalAlignment(JTextField.CENTER);screen.setEditable(false);Container c = getContentPane();c.setLayout(new BorderLayout());c.add(panel, BorderLayout.SOUTH);c.add(screen, BorderLayout.CENTER);this.setSize(200, 150);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);this.setResizable(false);this.setLocationRelativeTo(null);this.setVisible(true);}public static void main(String[] args) {new TimerDemo(1);// 设定 1ms/次// new TimerDemo();}@Overridepublic void actionPerformed(ActionEvent e) {if (e.getSource() == start) {if (start.getText().equals("开始")) {start.setText("暂停");isRunning = true;} else if (start.getText().equals("暂停")) {start.setText("开始");isRunning = false;}}if (e.getSource() == reset) {start.setText("开始");screen.setText("0");isRunning = false;time = 0;}new Thread(new TimeZone()).start();}class TimeZone implements Runnable {@Overridepublic void run() {while (isRunning) {time;if (time = Integer.MAX_VALUE) {screen.setText("ERROR");JOptionPane.showMessageDialog(null, "ERROR");isRunning = false;}screen.setText(String.valueOf(time));try {Thread.sleep(timeBetween);} catch (Exception e) {e.printStackTrace();}}}}}
java编写计算器实现退格,倒数,小数点,正负号功能代码import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class General extends JFrame implements ActionListener
{
String args[]={"退格","总清","清零","/","1","2","3"," ","4","5","6","-","7","8","9","*","0"," /-",".","="};
JButton jb[]=new JButton[20];
JPanel p1=new JPanel();
JTextField jtf=new JTextField(15);
【java计算机倒数代码 java倒叙输出数字】 double num1,num2,jieguo;
char c,ch;
public General()
{
Container ct=getContentPane();
jtf.addKeyListener(new KA());
jtf.setHorizontalAlignment(JTextField.RIGHT);
ct.add(jtf,"North");
p1.setLayout(new GridLayout(5,4));
for(int i=0;i20;i)
{
jb[i]=new JButton(args[i]);
jb[i].addActionListener(this);
p1.add(jb[i]);
}
ct.add(p1);
pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String args[])
{
new General();
}
public void actionPerformed(ActionEvent e)// 监听按键
{
String str=e.getActionCommand().trim();
if("0123456789.".indexOf(str)!=-1)
{
if(jtf.getText().equals("0"))jtf.setText(null);
jtf.setText(jtf.getText() str);
return;
}
if(" -*/".indexOf(str)!=-1)
{
num1=Double.parseDouble(jtf.getText());
c=str.charAt(0);
jtf.setText(null);
return;
}
else if(str.equals("="))
{
num2=Double.parseDouble(jtf.getText());
switch(c)
{
case ' ': jieguo=num1 num2; break;
case '-': jieguo=num1-num2; break;
case '*': jieguo=num1*num2; break;
case '/': jieguo=num1/num2; break;
}
jtf.setText(Double.toString(jieguo));
}
else if(str.equals(" /-"))
{
if(jtf.getText().isEmpty()==false)
{
Double lnum=-(Double.parseDouble(jtf.getText()));
jtf.setText(Double.toString(lnum));
}
else
{
jtf.setText("-");
}
}
else if(str.equals("清空"))
{
jtf.setText(null);
}
else if(str.equals("清零"))
{
jtf.setText("0");
}
else if(str.equals("退格"))
{
jtf.setText(jtf.getText().substring(0,jtf.getText().length()-1));
}
}
class KA extends KeyAdapter //监听键盘
{
public void keyPressed(KeyEvent e)
{
char ch=e.getKeyChar();
if(" -*/".indexOf(ch)!=-1)
{
num1=Double.parseDouble(jtf.getText());
c=ch;
}
if(ch=='='|ch==e.VK_ENTER)
{
num2=Double.parseDouble(jtf.getText());
switch(c)
{
case ' ': jieguo=num1 num2; break;
case '-': jieguo=num1-num2; break;
case '*': jieguo=num1*num2; break;
case '/': jieguo=num1/num2; break;
}
}
}
public void keyReleased(KeyEvent e)
{
char ch=e.getKeyChar();
if(" -*/".indexOf(ch)!=-1)
{
jtf.setText(null);
}
if(ch=='='|e.getKeyCode()==e.VK_ENTER)
{
jtf.setText(Double.toString(jieguo));
}
}
}
}
怎么编写一个倒计时的java的程序?求具体步骤!基于控制台的话很简单的,我跟你说一下大体思路吧 , 二话不说先来个for循环 , 然后输出倒计时的数字,程序睡一秒,在输出倒计时数字,如此循环,简单吧,下面看程序:
public static void main(String[] args) {
for(int i=10;i0;i--){
System.out.print(i " ");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.err.print("爆炸");
}
其他基于网页的还是基于用户界面都可以使用这个思路的
java编程求某个数的相反数,倒数,绝对值//倒数
double y=(double)1/123;//1除以任何数 就是java计算机倒数代码他本身java计算机倒数代码的倒数这里把1/123强转为double类型
System.out.println("y的倒数为" y);
int x =123;//x可以为任意数0-x就是x的相反数
System.out.println((0-x));
//绝对值
int a =-15;
int b=Math.abs(a);
System.out.println(b);
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