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import java.awt.Dimension;
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import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Painter extends JFrame{
/**
*
*/
private static final long serialVersionUID = 8160427604782702376L;
CanvasPanel canvas = new CanvasPanel();;
public Painter() {
super("Star");
this.add(canvas);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setResizable(false);
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public static void main(String[] args) {
new Painter();
}
}
class CanvasPanel extends JPanel implements ActionListener{
/**
*
*/
private static final long serialVersionUID = -4642528854538741028L;
private JButton[] btn = new JButton[4];
private String[] btn_name = {"+", "-", "R", "L"};
private int center_x = 200, center_y = 200, radius = 100, degree = 0;
public CanvasPanel() {
this.setPreferredSize(new Dimension(400, 500));
this.setLayout(null);
for(int i = 0; i 4; i++) {
btn[i] = new JButton(btn_name[i]);
btn[i].setBounds(160 + i * 60, 425, 50, 50);
btn[i].addActionListener(this);
this.add(btn[i]);
}
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for(int i = 0; i 5; i++) {
g.drawLine( (int) (center_x + radius * Math.sin(Math.toRadians(degree + 72 * i))),
(int) (center_y - radius * Math.cos(Math.toRadians(degree + 72 * i))),
(int) (center_x + radius * Math.sin(Math.toRadians(degree + 72 * i + 144))),
(int) (center_y - radius * Math.cos(Math.toRadians(degree + 72 * i + 144))));
}
}
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand() == "+") {
if(radius 200)
radius += 2;
repaint();
} else if(e.getActionCommand() == "-") {
if(radius 0)
radius -= 2;
repaint();
} else if(e.getActionCommand() == "R") {
degree = (degree + 2) % 360;
repaint();
} else if(e.getActionCommand() == "L") {
degree = (degree - 2) % 360;
repaint();
}
}
}
//Example.java
class A{
float a;
static float b;
void setA(float a ){
this.a = a;
}
void setB(float b){
this.b = b;
}
float getA() {
return a;
}
float getB() {
return b;
}
void inputA() {
System.out.println(a);
}
static void inputB() {
System.out.println(b);
}
}
public class Example {
public static void main (String args[]){
/*代码5] //通过类名操作类变量b，并赋值100
[代码6] //通过类名调用方法inputB（）
A cat=new A();
A dog=new A();
[代码7] //cat调用方法setA（int a）将cat的成员a的值设置为200
[代码8] //cat调用方法setB（int b）将cat的成员b的值设置为400
[代码9] //dog调用方法setA（int a）将dog的成员a的值设置为300
[代码10] //dog调用方法setB（int b）将dog的成员b的值设置为800
[代码11] //cat调用方法inputA（）
[代码12] //cat调用方法inputB（）
[代码13] //dog调用方法inputA（）
[代码14] //dog调用方法inputB（）*/
A.b = 100;
A.inputB();
A cat = new A();
A dog = new A();
cat.setA(200);
cat.setB(300);
dog.setA(300);
dog.setB(800);
cat.inputA();
cat.inputB();
dog.inputA();
dog.inputB();
}
}
有一个要说明的是，setA()与setB()的形参是浮点型的，所以如楼上所说，楼主代码7到代码10的形参设错了。但200，400，300，800是可以的。只是将int改为float.
给你一个前几天才帮人写的
“计算整钱兑零”。程序要求用户输入一个双精度数代表总元数，就会列出总值与其等价的1元币、二角五分币、5分币和1分币的数目。程序报告的数目是1元币的最大数、其次是二角五分币的最大数，等等，依此类推。只显示非零的单位。对单个单位显示单数单词，对多于一个单位的显示复数单词
import java.util.Scanner;
public class MoneyCalculate {
public static void main(String[] args) {
int max100 = 0;
int max25 = 0;
int max5 = 0;
int max1 = 0;
double money = getMoneyFromInput();
String str = String.valueOf(money).trim();
String[] ary = str.split("\\.");
max100 = Integer.parseInt(ary[0]);
if(ary.length == 2){
int fen = Integer.parseInt(ary[1]);
if(ary[1].trim().length() == 1){
fen = Integer.parseInt(ary[1]) * 10;
}
max25 = fen / 25;
if(fen % 25 != 0){
fen = fen % 25;
}else{
fen = 0;
}
max5 = fen / 5;
max1 = fen % 5;
}
StringBuilder sb = new StringBuilder(money + " = ");
if(max100 != 0){
sb.append(max100);
sb.append("*1 ");
}
if(max25 != 0){
sb.append(max25);
sb.append("*0.25 ");
}
if(max5 != 0){
sb.append(max5);
sb.append("*0.05 ");
}
if(max1 != 0){
sb.append(max1);
sb.append("*0.01 ");
}
System.out.println(sb.toString());
}
private static double getMoneyFromInput() {
Scanner scanner = new Scanner(System.in);
return scanner.nextDouble();
}
}
-----------
2.49
2.49 = 2*1 1*0.25 4*0.05 4*0.01
-----------
2.5
2.5 = 2*1 2*0.25
-----------
37.23
37.23 = 37*1 4*0.05 3*0.01
-----------------
123.569
123.569 = 123*1 22*0.25 3*0.05 4*0.01