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1.switch方法和for循环要学会结合使用。 2.While 发牌 public static void main(String[] args) { // TODO Auto-generated method stub String [] player = {“周星驰”,“周润发”,“小沈阳”}; String [] cards = {“黑桃A”,“黑桃K”,“黑桃Q”,“红桃2”,“红桃3”,“红桃4”,“方片J”,“方片k”,“方片5”}; int index = 0; while(index <cards.length){ String card = cards[index]; String people = player[index++%3]; System.out.print(people+":"+card+" "); if(index % 3==0){ System.out.println(); } } 3. While 猜数字 public static void main(String[] args) { // TODO Auto-generated method stub int boss = 500;//int number =(int)(Math.random*1000); System.out.println(“请开始猜数字：”); Scanner sc = new Scanner(System.in); int guess = sc.nextInt(); while(guess!= boss){ if(guess<boss){ System.out.println(“猜小了”); } else{ System.out.println(“猜大发了”); } System.out.println(“再给你一次机会：”); guess = sc.nextInt(); } if(guess == boss){ System.out.println(“恭喜通关”); }

} 1 Do-While 猜数字 public static void main(String[] args) { // TODO Auto-generated method stub int boss=(int)(Math.random()*1000); System.out.println(“boss=”+boss); System.out.println(“请输入一个整数：”); Scanner sc = new Scanner(System.in); int guess ; do{ guess = sc.nextInt(); if(guess < boss){ System.out.println(“输入过小”); }else{ System.out.println(“输入过大”); } System.out.println(“请重新输入:”); guess= sc.nextInt(); }while(guess != boss); if(guess == boss){ System.out.println(“恭喜恭喜！！！！！！”); } } 4.switch 表达式的取值：byte,short , int ,char ;;;;;JDK5加入了枚举 JDK7加入了String

package cn.ll.day02;

import java.awt.Color; import java.awt.Font; import java.awt.Graphics;

import javax.swing.JPanel;

public class MyJpane extends JPanel implements Runnable{ int x1=300; int y1=300; int y2=390; int x4=260; int x3=400; int x5=450; int x6=40; int x7=600; //钱----存储所有的x和y坐标 int[] x12=new int[50]; int[] y12=new int[50];

public MyJpane(){ for(int i =0;i<x12.length;i++){ x12[i]= (int)(Math.random()*1400); y12[i]=(int)(Math.random()*800); } //创建线程 Thread t=new Thread(this); t.start(); public void paint(Graphics g){ //g:画笔 super.paint(g); g.setColor(Color.BLUE); g.setFont(new Font(Font.DIALOG, Font.BOLD, 50)); g.drawString(“521”, 440, 440); g.drawString(“老詹”, y2, 390); this.setBackground(Color.black); g.fillOval(x1, y1, 100, 100); g.setColor(Color.black); g.fillOval(x1, y1, 80, 80); g.setColor(Color.cyan); g.drawRect(x3,400,x4,80); g.fillOval(400+50, 400+50, 40, 40); g.fillOval(550+50, 400+50, 40, 40); //画字符 for(int i=0;i<x12.length;i++){ g.setColor(Color.orange); g.setFont(new Font(Font.DIALOG, Font.BOLD, 60)); g.drawString("$", x12[i], y12[i]); }

} public void run(){ while(true){ //月亮移动 x1++; for(int i=0;i<x12.length;i++){ y12[i]++; if(y12[i]>=800){ y12[i]=0; } }

if(x1>=800){ x1=0; }

repaint();//重绘，重复调用paint方法 try { Thread.sleep(15); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }