JAVA经典实用程序代码

1百分制分数到等级分数package pm;public class SwitchTest /编写程序，实现从百分制分数到等级分数的转换 /=90 A/ 8089 B/ 7079 C/ 6069 D/ 60 E public static void main(String args) int s=87;switch(s/10) case 10 :System.out.println(A);break; case 9 :System.out.println(A);break; case 8 :System.out.println(B);break;case 7 :System.out.println(c);break;case 6 :System.out.println(D);break;default :System.out.println(E);break; 2成法口诀阵形package pm;public class SwitchTestpublic static void main(String args) for(int i=1;i=9;i+) for(int j=1;jb?a:b;d=ab?(ac?a:c):(bc?b:c);System.out.println(最多数为：+d);5简单计算器的小程序package one;import java.awt.BorderLayout;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.JPanel;import javax.swing.JTextField;public class Jsq implements ActionListener private JFrame frame;private JButton bus;private JTextField jtx;private JButton bu;private char strs;private String d_one = ;private String operator;public static void main(String args) new Jsq();/* 利用构造进行实例化 */public Jsq() frame = new JFrame(计算器);jtx = new JTextField(14);bus = new JButton16;strs = 789/456*123-0.+=.toCharArray();for (int i = 0; i 16; i+) busi = new JButton(strsi + );busi.addActionListener(this);bu = new JButton(C);bu.addActionListener(this);init();/* GUI 初始化 */public void init() JPanel jp1 = new JPanel();jp1.add(jtx);jp1.add(bu);frame.add(jp1, BorderLayout.NORTH);JPanel jp2 = new JPanel();jp2.setLayout(new GridLayout(4, 4);for (int i = 0; i 16; i+) jp2.add(busi);frame.add(jp2, BorderLayout.CENTER);frame.pack();frame.setLocation(300, 400);frame.setVisible(true);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);/* 事件的处理 */public void actionPerformed(ActionEvent arg0) /*获取输入字符*/String conn = arg0.getActionCommand();/*清除计算器内容*/if (C.equals(conn) d_one = ;operator = ;jtx.setText();return;/*暂未实现该功能*/if(.equals(conn)return;/*记录运算符，保存运算数字*/if (+-*/.indexOf(conn) != -1) if(.equals(d_one) & .equals(jtx.getText() return;d_one = jtx.getText();operator = conn;jtx.setText();return;/*计算结果*/if (=.equals(conn) if(.equals(d_one) & .equals(jtx.getText() return;double db = 0;if (+.equals(operator) db = Double.parseDouble(d_one)+ Double.parseDouble(jtx.getText();jtx.setText(db + );if (-.equals(operator) db = Double.parseDouble(d_one)- Double.parseDouble(jtx.getText();jtx.setText(db + );if (*.equals(operator) db = Double.parseDouble(d_one)* Double.parseDouble(jtx.getText();jtx.setText(db + );if (/.equals(operator) db = Double.parseDouble(d_one)/ Double.parseDouble(jtx.getText();jtx.setText(db + );d_one = db + ;return;/界面显示jtx.setText(jtx.getText() + conn);6三角形图案package pm;public class SwitchTestpublic static void main(String args) int n=5; for(int i=0;i=n;i+) for(int j=0;jn-i;j+) System.out.print( ); for(int k=0;k=a & firstChar=A & firstChar=0)hour=time/3600;minute=(time-hour*3600)/60;seconds=time-hour*3600-minute*60;jl1.setText(hour+时);jl2.setText(minute+分);jl3.setText(seconds+秒);try Thread.sleep(1000); catch (InterruptedException e) e.printStackTrace();time-;/*构造 实现界面的开发 GUI */public SwitchTest()frame = new JFrame(倒计时);jl1 = new JLabel();jl2 = new JLabel();jl3 = new JLabel();init();/*组件的装配*/private void init()JPanel jp=new JPanel();jp.add(jl1);jp.add(jl2);jp.add(jl3);frame.add(jp);frame.setVisible(true);frame.setLocation(300,400);frame.setSize(300, 200);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);9棋盘图案public class Sjxpublic static void main(String args) int SIZE=19; for(int i=0;iSIZE;i+) if(i10) System.out.print( +i);/两个空格 else System.out.print( +(char)(i+a-10);/两个空格 System.out.println(); / System.out.print(i10?(char)(i+0):(char)(i+a-10); for(int i=0;iSIZE;i+) if(i10) System.out.print(i+ );/一个空格 else System.out.print(char)(i+a-10)+ );/一个空格 for(int j=0;jSIZE;j+) System.out.print(*+ );/两个空格 System.out.println(); 10数组输出唐诗package day04;public class ArrayTest public static void main(String args) char arr=new char47; String s=朝辞白帝彩云间千里江陵一日还两岸猿声啼不住轻舟已过万重山; for(int i=0;iarr.length;i+) for(int j=0;jarri.length;j+) arrij=s.charAt(i*7+j); for(int i=0;iarr0.length;i+) for(int j=0;jarr.length;j+) System.out.print(arrarr.length-j-1i+ ); System.out.println(); 11找出满足条件的最小数package day02;public class Fangkpublic static void main(String args)/for(int i=1000;ib & sg & q+g=b+s & b%2!=0)/System.out.println(The Min Number is:+i);/break;/loop1:for(int q=1;q=9;q+)loop2:for(int b=0;b=9;b+) if(b%2=0) continue loop2; for(int s=0;s=9;s+)for(int g=0;gb & sg & q+g=b+s)System.out.println(The Min Number is:+(q*1000+b*100+s*10+g);break loop1;12判断一个数是否是素数package day02;public class Fangkpublic static void main(String args)int num=14;boolean flag=true;for(int i=2;i=num/2;i+)if(num%i=0)flag=false;break;if(flag)System.out.println(num+ is a prime number!);elseSystem.out.println(num+ is not a prime number!);/package day04;import java.util.Scanner;public class A1 public static void main(String args) int n; Scanner sca=new Scanner(System.in); System.out.println(please input a number:); n=sca.nextInt(); if(isPrimeNumber(n) System.out.println(n+is a prime number!); else System.out.println(n+is not a prime number!); public static boolean isPrimeNumber(int n) for(int i=2;i=n/2;i+) if(n%i=0) return false; return true; 13一个数倒序排列package day02;public class Daoxupublic static void main(String args)int olddata=3758;int newdata=0;while(olddata!=0)for(int i=0;i=0;i-) if(n&(1i)!=0) System.out.print(1); else System.out.print(0); if(32-i)%8=0) System.out.print( ); 15矩形图案package day02;public class Fangk public static void main(String args)int m=5,n=6;for(int i=0;in;i+)System.out.print(* );System.out.println(); for(int i=0;im-2;i+) System.out.print(* ); for(int j=0;jn-2;j+) System.out.print( ); System.out.print(*); System.out.println(); for(int i=0;i=0;i-)System.out.println(please input your number! );m=s.nextInt();if(mnum)System.out.println(Too large!); else if(m0)System.out.println(还有+i+次机会！);if( m!=num)System.out.println(下次再来吧！);17.HotelManagerpackage hotel;import java.util.Scanner;public class HotelManager private static String rooms;/ 表示房间public static void main(String args) rooms = new String1012;String comm;/ 表示用户输入的命令for (int i = 0; i rooms.length; i+) for (int j = 0; j rooms0.length; j+) roomsij = EMPTY;/while (true) System.out.println(请输入命令：);Scanner sca = new Scanner(System.in);System.gc();comm = sca.next();if (search.equalsIgnoreCase(comm) search(); else if (in.equalsIgnoreCase(comm) int roomNo = sca.nextInt();String name = sca.next();in(roomNo, name); else if (out.equalsIgnoreCase(comm) int roomNo = sca.nextInt();out(roomNo); else if (exit.equalsIgnoreCase(comm) System.out.println(程序退出.);break; else System.out.println(命令输入错误，请重新输入：);private static void out(int roomNo) if(EMPTY.equals(rooms(roomNo/100)-1(roomNo%100)-1)System.out.println(该房间没有客人入住，退房失败！);return;rooms(roomNo/100)-1(roomNo%100)-1=EMPTY;System.out.println(roomNo+退房成功！);private static void in(int roomNo, String name) if(!EMPTY.equals(rooms(roomNo/100)-1(roomNo%100)-1)System.out.println(该房间已经有客人入住！);return;rooms(roomNo/100)-1(roomNo%100)-1=name;System.out.println(name+成功入住+roomNo+房间！);private static void search() for (int i = 0; i rooms.length; i+) /打印房间号for (int j = 0; j rooms0.length; j+) if (j + 1 10) System.out.print(i + 1 + 0 + (j + 1) + ); else System.out.print(i + 1 + + (j + 1) + );/打印房间状态System.out.println();for (int j = 0; j rooms0.length; j+) System.out.print(roomsij + );System.out.println();18.StudentManagerpackage day05.student_manager;import java.util.Scanner;public class StudentManager static int scores=new int65;static String students=zhangsan,lisi,wangwu,zhaoliu,qianqi,liuba;static String courses=corejava,jdbc,servlet,jsp,ejb;public static void main(String args) for(int i=0;iscores.length;i+)for(int j=0;jscoresi.length;j+)scoresij=(int)(Math.random()*100);Scanner s=new Scanner(System.in);String comm;while(true)System.out.println(请输入命令：);comm=s.next();if(comm.equals(AVG)String para=s.next();avg(para);else if(comm.equals(SORT)String course=s.next();sort(course);else if(comm.equals(GET)String student=s.next();String course=s.next();get(student,course);else if(comm.equals(EXIT)break;elseSystem.out.println(命令格式不正确，请重新输入！);/main() end!public static void avg(String para) int sIndex=-1;int cIndex=-1;for(int i=0;istudents.length;i+)if(studentsi.equals(para)sIndex=i;if(sIndex=-1)for(int i=0;icourses.length;i+)if(coursesi.equals(para)cIndex=i;if(sIndex=-1 & cIndex=-1)System.out.println(找不到学生或课程！);return;double avg=0.0;if(sIndex!=-1)for(int i=0;iscoressIndex.length;i+)avg+=scoressIndexi;avg/=scoressIndex.length;System.out.println(学生：+para+的平均分是:+avg);elsefor(int i=0;iscores.length;i+)avg+=scoresicIndex;avg/=scores.length;System.out.println(课程：+para+的平均分是:+avg);public static void sort(String course)int courseScore=new intscores.length;if(course.equals(sum)/如果求总分的排名/求出每个学生的总分，将成绩存放在courseScore数组中for(int i=0;iscores.length;i+)int studentSum=0;for(int j=0;jscoresi.length;j+)studentSum+=scoresij;courseScorei=studentSum;else/如果不是求总分排名int cIndex=-1;for(int i=0;icourses.length;i+)/找到这门课程的下标if(coursesi.equals(course)cIndex=i;if(cIndex!=-1)/如果是一门有效的课程/把scores数组中这一列的值放到courseScore数组中！for(int i=0;iscores.length;i+)courseScorei=scoresicIndex;else/如果不是一门有效的课程System.out.println(课程名不正确，请重新输入！);return;String studentCopy=new Stringstudents.length;System.arraycopy(students, 0, studentCopy, 0, students.length);for(int i=0;icourseScore.length-1;i+)for(int j=i+1;jcourseScore.length;j+)if(courseScoreicourseScorej)int temp=courseScorei;courseScorei=courseScorej;courseScorej=temp;String stemp=studentCopyi;studentCopyi=studentCopyj;studentCopyj=stemp;int order=1;System.out.println(名次t学生t成绩);for(int i=0;icourseScore.length;i+)if(i!=0 & courseScorei=courseScorei-1)order-;elseorder=i+1;System.out.print(order+t);System.out.print(studentCopyi+t);System.out.println(courseScorei);order+;public static void get(String student,String course)int sIndex=-1;int cIndex=-1;for(int i=0;istudents.length;i+)if(studentsi.equals(student)sIndex=i;if(sIndex=-1)System.out.println(没有这个学生:+student);return;if(course.equals(sum)/如果求总分int studentSum=0;for(int j=0;jscoressIndex.length;j+)studentSum+=scoressIndexj;System.out.println(student+学生的总分为：+studentSum);return;for(int i=0;icourses.length;i+)if(coursesi.equals(course)cIndex=i;if(cIndex=-1)System.out.println(没有这门课程:+course);return;System.out.println(