Java 需要帮助制作一个随机数学生成器吗

我应该做的是：编写一个程序，给用户10道随机的数学题，每次都要问答案，然后告诉用户他们是对还是错。每个问题应该使用2个介于1和20之间的随机数，以及一个随机运算（+、-、*、或/）。你需要为每道数学题重新随机分配数字。你还应该记录他们解决了多少问题。最后，告诉用户他们解决了多少问题，并根据结果给他们一条消息。例如，你可以说“干得好”或“你需要更多的练习”

到目前为止，我感到不知所措

import java.util.Scanner; 

public class SS_Un5As4 {

 public static void main(String[] args){

 Scanner scan = new Scanner(System.in);

 int number1 = (int)(Math.random()* 20) + 1;

int number2 = (int)(Math.random()* 20) + 1;

 int operator = (int)(Math.random()*4) + 1;

  if (operator == 1)

  System.out.println("+"); 

 if (operator == 2) 

   System.out.println("-");

 if (operator == 3)

 System.out.println("*");

  if (operator == 4)
            System.out.println("/");  


      }
  }

---

我主要需要知道如何将这些随机数和运算符转化为一个问题，以及如何对每个问题进行评分以确定它们是否错误

打印出数字和操作，使用文件IO读取用户输入，并执行跟踪已回答问题的逻辑 代码：

跟踪结果并与用户输入进行比较，验证其正确性或错误性

公共静态void main（字符串[]args）引发IOException{

    int number1 = (int)(Math.random()* 20) + 1;
    int number2 = (int)(Math.random()* 20) + 1;
    int operator = (int)(Math.random()*4) + 1;
    String operation = null;
    int result=0;
    if (operator == 1){
        operation="+";
        result=number1+number2;
    }
    if (operator == 2) {
        operation="-";
        result=number1-number2;
    }
    if (operator == 3){
        operation="*";  
        result=number1*number2;
    }
    if (operator == 4){
        operation="/";
        result=number1/number2;
    }
    System.out.println("Question "+number1+operation+number2);
    String result1 = new BufferedReader(new InputStreamReader(System.in)).readLine();
    if(result==Integer.parseInt(result1))
        System.out.println("Right");
    else
        System.out.println("Wrong");
}

---

嗯，你需要补充的是：

• 要计算答案：
  • 计算正确答案的变量（每次用户正确回答时递增）
  • 用于存储当前正确答案的变量
  • 一个用于存储当前用户答案的变量（每出现一个问题就刷新一次，无需永远存储，因为在您的情况下只需要统计数据）
  • 一个函数（可以调用它，例如gradeTheStudent（）），它使用多个条件根据正确答案的数量决定打印内容
• 要产生问题：
  • 将问题生成和答案评估纳入一个循环，重复10次
  • 在您的开关中（即当您选择操作员时），也计算正确答案：

     switch(operator){
    
          case 1: {
          operation = "+";
          correctResult = number1 + number2;
          break;
       }
       case 2: ....
       case 3: ....
       case 4: ....
       default: break;
    }
    

  • 不要忘记检查用户是否输入了数字或其他内容（可以使用异常或简单条件）

因此，针对您的问题的“伪代码”解决方案如下所示：

  String[] reactions = ["Awesome!","Not bad!","Try again and you will get better!"]
  num1 = 0
  num2 = 0
  operator = NIL
  userScore = 0
  userAnswer = 0
  correctAnswer = 0

  def function main:

      counter = 0
      for counter in range 0 to 10:
          generateRandomNumbers()
          correctAnswer = generateOperatorAndCorrectAnswer()
          printQuestion()
          compareResult()

      gradeStudent()

  def function generateRandomNumbers:
      # note that you have already done it!

  def function generateOperatorAndCorrectAnswer:
      # here goes our switch!
      return(correctAnswer);

  def function printQuestion:
      print  "Next problem:" + "\n"
      print num1 + " " + operator + " " + num2 + " = " + "\n"

  def function compareResult(correctAnswer):
      # get user result - in your case with scanner
      if(result == correctAnswer) 
                print "Great job! Correct answer! \n"
                userScore++
      else print "Sorry, answer is wrong =( \n"

  def function gradeStudent (numOfCorrectAnswers):
      if(numOfCorrectAnswers >= 7) print reactions[0]
      else if(numOfCorrectAnswers < 7 and numOfCorrectAnswers >= 4) print reactions[1]
      else print reactions[2]

String[]responses=[“太棒了！”，“不错！”，“再试一次，你会好起来的！”
num1=0
num2=0
运算符=零
userScore=0
userAnswer=0
正确答案=0
def主功能：
计数器=0
对于0到10范围内的计数器：
generateRandomNumbers（）
correctAnswer=GenerateOperator和correctAnswer（）
打印问题（）
比较结果（）
年级学生（）
def函数生成器域编号：
#请注意，您已经完成了！
def函数生成器运算符和正确答案：
#我们的开关来了！
返回（正确答案）；
def功能打印问题：
打印“下一个问题：”+“\n”
打印num1+“”+运算符+“”+num2+“=”+“\n”
def功能比较结果（正确答案）：
#获取用户结果-在您使用扫描仪的情况下
如果（结果==正确答案）
打印“干得好！回答正确！\n”
用户分数++
否则打印“对不起，答案错误=（\n”
def功能等级学生（NUMOF）：
如果（numOfCorrectAnswers>=7）打印反应[0]
如果（numOfCorrectAnswers<7和numOfCorrectAnswers>=4）打印反应[1]
其他打印反应[2]

一般建议：不要试图一次解决所有问题。一个好的方法是创建小函数，每个函数都执行其独特的任务。问题分解也一样：你只需写下你认为需要什么来模拟情况，然后一步一步地进行

注意：从您当前的功能来看，您不熟悉Java中的面向对象编程。这就是为什么我不提供任何关于使用类有多好的提示。但是，如果您是，请告诉我，我将在我的帖子中添加信息

---

祝你好运！

例如，你可以使用这样的东西：

public class Problem {
    private static final int DEFAULT_MIN_VALUE = 2;
    private static final int DEFAULT_MAX_VALUE = 20;

    private int number1;
    private int number2;
    private Operation operation;

    private Problem(){
    }

    public static Problem generateRandomProblem(){
        return generateRandomProblem(DEFAULT_MIN_VALUE, DEFAULT_MAX_VALUE);
    }

    public static Problem generateRandomProblem(int minValue, int maxValue){
        Problem prob = new Problem();
        Random randomGen = new Random();

        int number1 = randomGen.nextInt(maxValue + minValue) + minValue;
        int number2 = randomGen.nextInt(maxValue + minValue) + minValue;

        prob.setNumber1(number1);
        prob.setNumber2(number2);

        int operationCode = randomGen.nextInt(4);
        Operation operation = Operation.getOperationByCode(operationCode);
        prob.setOperation(operation);

        return prob;
    }

    public int getNumber1() {
        return number1;
    }

    public int getNumber2() {
        return number2;
    }

    public Operation getOperation() {
        return operation;
    }

    public void setNumber1(int number1) {
        this.number1 = number1;
    }

    public void setNumber2(int number2) {
        this.number2 = number2;
    }

    public void setOperation(Operation operation) {
        this.operation = operation;
    }
}

和另一类用于等待操作：

public enum Operation {
    PLUS,
    MINUS,
    MULTIPLY,
    DIVIDE;

    public double operationResult(int n1, int n2) {
        switch (this) {
            case PLUS: {
                return (n1 + n2);
            }
            case MINUS: {
                return n1 - n2;
            }
            case MULTIPLY: {
                return n1 * n2;
            }
            case DIVIDE: {
                return n1 / n2;
            }
        }
        throw new IllegalArgumentException("Behavior for operation is not specified.");
    }

    public static Operation getOperationByCode(int code) {
        switch (code) {
            case 1:
                return PLUS;
            case 2:
                return MINUS;
            case 3:
                return MULTIPLY;
            case 4:
                return DIVIDE;
        }
        throw new IllegalArgumentException("Operation with this code not found.");
    }
}

---

但是您不必抛出IllegalArgumentException，还有其他处理意外参数的选项。

因为我不想给您这个问题的完整解决方案，而且您似乎对Java语言有一些了解，所以我将写下我将如何继续/更改您拥有的作为开始

首先，我将结果存储在运算符if语句中。结果是一个int

if (operator == 1) {
   operation="+";
   result=number1+number2;
}

之后，我会打印数学问题，等待用户回答

System.out.println("What is the answer to question: " +number1+operation+number2);
userResult = in.nextLine();      // Read one line from the console.
in.close(); // Not really necessary, but a good habit.

在这个阶段，您所要做的就是将结果与用户输入进行比较，然后打印一条消息

if(Integer.parseInt(userResult) == result) {
  System.out.println("You are correct!");
} else {
  System.out.println("This was unfortunately not correct.");
}

---

这个解决方案或多或少是psudo代码，并且缺少一些错误处理（例如，如果用户在答案中输入test），而且我会将其拆分为多个方法，而不是将其全部放在main（）中。下一步是使其面向对象（查看来自demi的答案）.祝你顺利完成你的程序。

你在这方面做了哪些尝试？我想说你已经完成了最难的部分。似乎我遗漏了一些东西，但我只是不知道如何去做。如果你能详细说明，那就太棒了。打印输出=？。阅读用户输入。检查答案并输出消息。你可能不想这样做您还可以将运算符存储在

String operators=“+-*/”中

。你可以在那里查找和打印。非常感谢，我非常知道如何做，我可以弹出所有问题，让对方回答，但我仍然不知道如何记录它们是否正确。如果OP真的理解OOP，完美的答案。+1

In regard to generating random math operations with +, -, * & / with random numbers your can try the following;


import java.util.*;
public class RandomOperations{
   public static void main(String[] args){

       Random `mathPro` = new Random();
       //for the numbers in the game
       int a = mathPro.nextInt(50)+1;
       int b = mathPro.nextInt(50)+1;

       //for the all the math operation result

       int add = a+b;
       int sub = a-b;
       int mult = a*b;
       int div = a/b;
       //for the operators in the game

       int x = mathPro.nextInt(4);

       /*
         -so every random number between 1 and 4 will represent a math operator

         1 = +
         2 = -
         3 = x
         4 = /

      */

       if(x == 1){

          System.out.println("addition");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(add);

       }else if(x == 2){

          System.out.println("subtraction");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(sub);

       }else if(x == 3){

          System.out.println("multiplication");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(mult);

       }else{

          System.out.println("division");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(div);

       }
  //This os for the user to get his input then convert it to a numbers that the program can
  //understand
       Scanner userAnswer = new Scanner(System.in);
               System.out.println("Give it a try");
                 int n = `userAnswer.nextInt();

In regard to generating random math operations with +, -, * & / with random numbers your can try the following;


import java.util.*;
public class RandomOperations{
   public static void main(String[] args){

       Random `mathPro` = new Random();
       //for the numbers in the game
       int a = mathPro.nextInt(50)+1;
       int b = mathPro.nextInt(50)+1;

       //for the all the math operation result

       int add = a+b;
       int sub = a-b;
       int mult = a*b;
       int div = a/b;
       //for the operators in the game

       int x = mathPro.nextInt(4);

       /*
         -so every random number between 1 and 4 will represent a math operator

         1 = +
         2 = -
         3 = x
         4 = /

      */

       if(x == 1){

          System.out.println("addition");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(add);

       }else if(x == 2){

          System.out.println("subtraction");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(sub);

       }else if(x == 3){

          System.out.println("multiplication");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(mult);

       }else{

          System.out.println("division");
          System.out.println("");
          System.out.println(a);
          System.out.println(b);
          System.out.println(div);

       }
  //This os for the user to get his input then convert it to a numbers that the program can
  //understand
       Scanner userAnswer = new Scanner(System.in);
               System.out.println("Give it a try");
                 int n = `userAnswer.nextInt();