求教大佬！java实现随机出题

public class test {

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public static void main(String[] args) {

// java实现随机出题

// 50以内的加减乘除法，用户解答后系统判断对错，用户输入-1时中止训练

Scanner scan = new Scanner(System.in);

char[] arr = {'+','-','*','÷'};

while (true) {

// 生成一个随机小数，范围从 2.25 到 2.75的两位小数

// double sum = Math.random()*(2.75-2.25)+2.25;

int a = (int) (Math.random()*(50-0)+0);

int b = (int) (Math.random()*(50-0)+0);

int f = (int) (Math.random()*(4-0)+0);

if (f== 1 a b) {

continue;

}

if (f== 3 a == 0) {

continue;

}

System.out.println("题目:"+a+arr[f]+b+"=\n请输入:");

double sum = 0;

if (f == 0) {

sum = a+b;

}

if (f == 1) {

sum = a-b;

}

if (f == 2) {

sum = a*b;

}

if (f == 3) {

sum = 1.0*a/b;

}

double s = scan.nextDouble();

if (s == -1) {

System.err.println("结束");

break;

}

if (s == sum) {

System.err.println("正确");

}else {

System.err.println("错误");

}

}

}

}

Java随机数代码怎么写

Math.random()是令系统随机选取大于等于 0.0 且小于 1.0 的伪随机 double 值，是Java语言常用代码。

例如：var a:Number=Math.random()*2+1，设置一个随机1到3的变量。

Java随机抽取人名完整代码是什么？

public class test {\x0d\x0a public static void main(String[] args) {\x0d\x0a //定义人名数组\x0d\x0a String [] name = {"张三","李四","王五","八神庵","不知火舞","大蛇","景天","唐雪见","李逍遥","赵灵儿"};\x0d\x0a//随机生成数组下标、\x0d\x0a int num = (int)(Math.random() * 1000);\x0d\x0a//对生成的随机数进行判断，如果小于数组下标，就跳出循环\x0d\x0awhile (numname.length-1) {\x0d\x0a if (num

回答于 2022-11-16

如何用Java实现随机出题？

import java.io.*;

import java.sql.*;

import javax.servlet.*;

import javax.servlet.http.*;

import oracle.jdbc.driver.OracleDriver;

public class GenPaperServlet extends HttpServlet

{

Connection conn;

Statement stmt;

ResultSet rs;

int total_question_num;

int total_question_in_paper;

int total_paper_num;

String curr_classid;

public GenPaperServlet()

{

conn = null;

stmt = null;

rs = null;

total_question_num = 0;

total_question_in_paper = 0;

total_paper_num = 0;

curr_classid = "";

}

public void doGet(HttpServletRequest httpservletrequest, HttpServletResponse httpservletresponse)

throws ServletException, IOException

{

httpservletresponse.setContentType("text/html;charset=GBK");

PrintWriter printwriter = httpservletresponse.getWriter();

printwriter.println("htmlhead/headbodycenter");

printwriter.println("请以POST方式提交");

printwriter.println("/center/body/html");

printwriter.close();

}

public void doPost(HttpServletRequest httpservletrequest, HttpServletResponse httpservletresponse)

throws ServletException, IOException

{

httpservletresponse.setContentType("text/html;charset=GBK");

PrintWriter printwriter = httpservletresponse.getWriter();

String s = httpservletrequest.getParameter("classid"); //"20"

String s1 = httpservletrequest.getParameter("paper_num"); //"1"

if(s == null || s1 == null)

{

printwriter.println("center");

printwriter.println("请按照正常方式提交数据br");

printwriter.println("a href=/test/admin/genpaper.jsp单击这里设置生成试卷的参数/a");

printwriter.println("/center");

}

total_paper_num = Integer.parseInt(s1);

curr_classid = s;

int i = 0;

if(!open_db(curr_classid))

{

printwriter.println("打开数据库错误！");

return;

}

if(!setParams(curr_classid))

{

System.out.println("设置系统参数错误！");

return;

}

if(!verify_QuertionLib())

{

printwriter.println("试题库中试卷不足，请增加新的试题！");

printwriter.println("班级代号：" + curr_classid);

printwriter.println("该班级一套试卷中的试题数：" + total_question_in_paper);

printwriter.println("目前题库中该班级的试题总数：" + total_question_num);

return;

}

i = genPaper(total_paper_num, curr_classid);

if(i == 0)

{

printwriter.println("生成试卷操作失败！");

return;

}

if(!updateOtherTable(i, curr_classid))

{

printwriter.println("更新相关表操作失败！");

return;

} else

{

printwriter.println("center");

printwriter.println("动态组卷成功！br");

printwriter.println("共生成了 " + i + " 套试卷br");

printwriter.println("a href=/test/admin/genpaper.jsp单击这里设置生成试卷的参数/a");

printwriter.println("/center");

return;

}

}

public boolean open_db(String s)

{

try

{

new OracleDriver();

conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ora9", "scott", "tiger");

stmt = conn.createStatement();

}

catch(Exception exception)

{

return false;

}

return true;

}

public boolean setParams(String s)

{

String s1 = "";

try

{

String s2 = "select count(questionid) as countquestionid from test_question_lib ";

s2 = s2 + "where classid='" + s + "'";

rs = stmt.executeQuery(s2);

rs.next();

total_question_num = rs.getInt("countquestionid");

s2 = "select totalques from test_classinfo ";

s2 = s2 + "where classid='" + s + "'";

rs = stmt.executeQuery(s2);

rs.next();

total_question_in_paper = rs.getInt("totalques");

}

catch(Exception exception)

{

return false;

}

return true;

}

public boolean verify_QuertionLib()

{

return total_question_num = total_question_in_paper;

}

public boolean updateOtherTable(int i, String s)

{

int j = 0;

String s1 = "update test_classinfo set totalpaper=totalpaper+";

s1 = s1 + i + " where classid='" + s + "'";

try

{

j = stmt.executeUpdate(s1);

}

catch(Exception exception)

{

return false;

}

return j == 1;

}

public int genPaper(int i, String s)

{

boolean flag = false;

boolean flag1 = false;

boolean flag2 = false;

boolean flag3 = false;

String s1 = "";

try

{

int ai[] = new int[total_question_num];

int i1 = 0;

boolean flag4 = false;

String s2 = "select max(paper_id) as max_paper_id from test_paper_lib";

rs = stmt.executeQuery(s2);

rs.next();

int j = rs.getInt("max_paper_id") + 1;

s2 = "select questionid from test_question_lib where classid='" + s + "'";

for(rs = stmt.executeQuery(s2); rs.next();)

ai[i1++] = rs.getInt("questionid");

for(int k1 = 0; k1 i; k1++)

{

int k = ai.length; //8

for(int l1 = 0; l1 total_question_in_paper; l1++)

{

// int ai[] ={1 ,3 , 5 ,9 , 56,30 96 ,25};

int j1 = (int)Math.floor(Math.random() * (double)k); // 4

String s3 = "insert into test_paper_lib values(";

s3 = s3 + "test_seq_paper.nextval," + j + "," + ai[j1] + ")";

stmt.executeUpdate(s3);

int l = ai[k - 1];

ai[k - 1] = ai[j1];

ai[j1] = l;

k--;

}

j++;

}

}

catch(Exception exception)

{

return 0;

}

return i;

}

}

（java）题库中有20道题，随机抽10道不同的题出来 怎么写代码 在线等啊

import java.util.*;

class Untitled {

public static void main(String[] args) throws Exception {

Integer[] questions = generateQuestions();

for(Integer question : questions) {

System.out.println(question);

}

}

private static Integer[] generateQuestions() {

ListInteger questionNumbers = new ArrayListInteger();

Random rand = new Random();

int questionNumber, i = 0;

while(i  10) {

questionNumber = rand.nextInt(21);

if(!questionNumbers.contains(questionNumber)) {

questionNumbers.add(questionNumber);

i ++;

}

}

return questionNumbers.toArray(new Integer[10]);

}

}

用java随机出100道题

1、首先对这几百道题逐一编号(假如有500道)。

2、用一个数组存放这些编号（从1-500）

3、用以下代码

ListInteger noList = new ArrayListInteger();

//把500个编号放入noList中

for(int i=1; i=500; i++)

{

noList.add(i);

}

int inx = 100;

//存放被随机选中的题目编号

ListInteger selectList = new ArrayListInteger();

while(inx0)

{

Random r = new Random();

int s = r.nextInt(noList.size());

selectList.add(noList.remove(s));

inx--；

}

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