第一类题目：1：public class exer {public static void main(String[] args) {int a=1+(int)(Math.random()*3000);boolean isprime=true;for(int k=2;k<=a/2;k++){if(a%k==0) isprime=false;break;}if(isprime) System.out.println(a+"是素数");else System.out.println(a+"不是素数");}}（2）public class exer {public static void main(String[] args) {for(int i=10000;i<=100000;i=i+10000){double sum=1;double e=1;for(int k=1;k<=i;k++){sum*=k;e+=1.0/sum;}System.out.println("当i的值为"+i+"时e的值为"+e);}}}（4）public class exer {public static void main(String[] args) { int[] a={1,4,7,9,12};for(int i=0;i<=2;i++){int temp;temp=a[i];a[i]=a[4-i];a[4-i]=temp;}for(int i=0;i<=4;i++){System.out.print(a[i]+" ");}}}第二类题目1：public class exer21 {public static void main(String[] args) { Triangle t=new Triangle(1,1.5,1);t.setcolor("yellow");t.setfilled(true);System.out.println(t.toString()+"\n周长为"+t.getPerimeter()+"\n 面积为"+t.getArea()+"\n颜色为"+t.getcolor()+"\n是否填充："+t.getfilled());}}abstract class GeometricObject{protected String color;protected boolean filled;;abstract public double getArea();abstract public double getPerimeter();}class Triangle extends GeometricObject{private double side1;private double side2;private double side3;public Triangle(){side1=1;side2=1;side3=1;}public Triangle(double side1,double side2,double side3){ this.side1=side1;this.side2=side2;this.side3=side3;}public void setside1(double side1){this.side1=side1;}public double getside1(){return side1;}public void setside2(double side2){this.side2=side2;}public double getside2(){return side2;}public void setside3(double side3){this.side3=side3;}public double getside3(){return side3;}public void setcolor(String color){this.color=color;}public String getcolor(){return color;}public void setfilled(boolean filled){this.filled=filled;}public boolean getfilled(){return filled;}public double getArea() {double s=(side1+side2+side3)/2;double area=Math.sqrt(s*(s-side1)*(s-side2)*(s-side3));return area;}@Overridepublic double getPerimeter() {return side1+side2+side3;}public String toString(){return"三角形的三条边为:"+side1+"、 "+side2+"、 "+side3;}}2.3public class exer23 {public static void main(String[] args) {System.out.println("------------ 储存账户 ------------");savingaccount debitCardAccount = new savingaccount("CHK1", 100, 0.01);// 初始余额有100元，调用并打印取90元和取120元的结果。

System.out.println("取90元的结果：" +debitCardAccount.getmoney(90));// 重新存入90元debitCardAccount.storemoney(90);System.out.println("取120元的结果：" +debitCardAccount.getmoney(120));// 创建一个可以透支的信用卡账户。

System.out.println("------------ 支票账户 ------------");checkingaccount crebitCardAccount = new checkingaccount("CHK2", 100, 0.02, 50);// 初始余额有100元，并且透支限度为50元，调用并打印取90元、取120元和取160元的结果。

System.out.println("取90元的结果：" +crebitCardAccount.getmoney(90));// 重新存入90元crebitCardAccount.storemoney(90);System.out.println("取120元的结果：" +crebitCardAccount.getmoney(120));// 重新存入120元crebitCardAccount.storemoney(120);System.out.println("取160元的结果：" +crebitCardAccount.getmoney(160));}}class Account{private String accountNumber;protected double overage;//余额private double annualInterestRate;//年利息public Account(String accountNumber, double overage,double annualInterestRate){this.accountNumber=accountNumber;this.overage=overage;this.annualInterestRate=annualInterestRate;}public void storemoney(double money){this.overage+=money;}public boolean getmoney(double money){if(this.overage<money)return false;else{this.overage-=money;return true;}}}class savingaccount extends Account {public savingaccount(String accountNumber, double overage,double annualInterestRate) {super(accountNumber, overage, annualInterestRate);}}class checkingaccount extends Account {private double overdraftLimit; // 透支限度public checkingaccount(String accountNumber, double overage,double annualInterestRate, double overdraftLimit) {super(accountNumber, overage, annualInterestRate);this.overdraftLimit = overdraftLimit;}public double getOverdraftLimit() {return this.overdraftLimit;}public void setOverdraftLimit(double overdraftLimit) {// 透支限度必须为零和正数，否则为零。

this.overdraftLimit = overdraftLimit >= 0 ? overdraftLimit : 0;}public checkingaccount(String accountNumber, double overage, double annualInterestRate) {super(accountNumber, overage, annualInterestRate); }public boolean getmoney(double money) {// 如果账户余额 + 透支限度的总金额仍不足，则不能取款if (this.overage + this.overdraftLimit < money) return false;// 否则从账户余额中扣除相应的金额this.overage -= money;return true;}}第三类：1：import java.awt.*;import java.util.Calendar;import java.util.GregorianCalendar;import javax.swing.JButton;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JTextField;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JFrame;public class clock extends JFrame{private int hour;private int minute;private int second;private JLabel l1=new JLabel("小时");private JLabel l2=new JLabel("分");private JLabel l3=new JLabel("秒");private JTextField t1=new JTextField(" ");private JTextField t2=new JTextField(" ");private JTextField t3=new JTextField(" ");private JButton b1=new JButton("设置");public clock(){J Panel p1=new JPanel();p1.setLayout(new FlowLayout(FlowLayout.LEFT,20,20));p1.add(l1);p1.add(t1);p1.add(l2);p1.add(t2);p1.add(l3);p1.add(t3);p1.add(b1);f inal StillClock c1=new StillClock(7,5,11);s etLayout(new BorderLayout());a dd(c1,BorderLayout.CENTER);a dd(p1,BorderLayout.SOUTH);b1.addActionListener(new ActionListener(){public void actionPerformed(ActionEvent arg0) {hour=Integer.parseInt(t1.getText().toString());minute=Integer.parseInt(t2.getText().toString());second=Integer.parseInt(t3.getText().toString());c1.sethour(hour);c1.sethour(minute);c1.sethour(second);repaint();}});}public static void main(String args[]){clock frame = new clock();frame.setTitle("text");frame.setSize(300, 300);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null);frame.setVisible(true);}class StillClock extends JPanel{private int hour;private int second;private int minute;public StillClock(int hour, int minute, int second) {this.hour = hour;this.minute = minute;this.second = second;}public void sethour(int honr){t his.hour=hour;}public void setminute(int minute){t his.minute=minute;}public void setsecond(int second){t his.second=second;}protected void paintComponent(Graphics g){super.paintComponent(g);int clockRadius = (int)((double)Math.min(getWidth(), getHeight()) * 0.8 * 0.5);int xCenter = getWidth() / 2;int yCenter = getHeight() / 2;g.setColor(Color.black);g.drawOval(xCenter - clockRadius, yCenter - clockRadius, 2 * clockRadius, 2 * clockRadius);g.drawString("12", xCenter - 5, (yCenter - clockRadius) + 12);g.drawString("9", (xCenter - clockRadius) + 3, yCenter + 5);g.drawString("3", (xCenter + clockRadius) - 10, yCenter + 3);g.drawString("6", xCenter - 3, (yCenter + clockRadius) - 3);int sLength = (int)((double)clockRadius * 0.8);int xSecond = (int)((double)xCenter + (double)sLength * Math.sin((double)second * 2*Math.PI/60 ));int ySecond = (int)((double)yCenter - (double)sLength * Math.cos((double)second * 2*Math.PI/60));g.setColor(Color.red);g.drawLine(xCenter, yCenter, xSecond, ySecond);int mLength = (int)((double)clockRadius * 0.65);int xMinute = (int)((double)xCenter + (double)mLength * Math.sin((double)minute * 2*Math.PI/60));int yMinute = (int)((double)yCenter - (double)mLength * Math.cos((double)minute * 2*Math.PI/60));g.setColor(Color.blue);g.drawLine(xCenter, yCenter, xMinute, yMinute);int hLength = (int)((double)clockRadius * 0.5);int xHour = (int)((double)xCenter + (double)hLength * Math.sin(((double)(hour % 12) + (double)minute / 60) * 2*Math.PI/12));int yHour = (int)((double)yCenter - (double)hLength * Math.cos(((double)(hour % 12) + (double)minute / 60) * 2*Math.PI/12));g.setColor(Color.green);g.drawLine(xCenter, yCenter, xHour, yHour);}}}。