需要幫助製作一個隨機的數學生成器

Question

我應該做的是這樣的：編寫一個程序，給用戶10個隨機數學問題，每次都要求答案，然後告訴用戶他們是對還是錯。每個問題應該使用1到20之間的2個隨機數，以及隨機操作（+， - ，*或/）。您需要重新隨機化每個數學問題的數字。你也應該跟蹤他們得到正確的問題。最後，告訴用戶他們得到的問題有多少，並根據他們的結果給他們留言。例如，你可能會說「幹得好」或「你需要更多的練習。」

到目前爲止，我很茫然

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("/"); 


     } 
    } 

我大多需要知道如何將這些隨機數字和運算成一個問題，以及如何對每個問題進行評分，看看他們是否錯了。

Answer 1

打印輸出的數量和操作，使用文件IO讀取用戶輸入，並執行保持的回答問題的軌道 代碼你的邏輯：

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; 
     String operation = null; 
     if (operator == 1) 
      operation="+";  
     if (operator == 2) 
       operation="-"; 
     if (operator == 3) 
      operation="*"; 
     if (operator == 4) 
      operation="/";  
     System.out.println("Question "+number1+operation+number2); 


    } 
} 

保持結果的一首曲目，用戶比較輸入驗證其對錯

公共靜態無效的主要（字串[] args）拋出IOException異常{

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"); 
} 

Answer 2

好，你需要補充的是：

• 來算的答案：

  • 計數正確答案（每用戶回答正確時加一）的變量;
  • 一個變量來存儲當前正確答案;
  • 一個變量來存儲當前用戶的答案（刷新它的每一個下一個問題，不需要永久存儲它，因爲在你的情況下只需要統計）;
  • 函數（讓它被稱爲例如gradeTheStudent（）），它使用幾個條件根據正確答案的數量決定打印出什麼;

• 創建一個問題：

  • 放問題的產生和回答評價成循環，其重複10次;
  • 在你的交換機

    （即當你選擇運營商）也算正確答案：

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

  • 不要忘記檢查，如果用戶輸入一個號碼或其他的東西（你可以使用任何異常或一個簡單的條件）。

因此，對於你的問題是「僞」的解決方案將是這個樣子：

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] 

一般的建議：不要試圖一下子解決問題。一個好的方法是創建小功能，每個功能都執行其獨特的任務。與問題分解一樣：你只需要寫下你認爲需要的東西，以便對情況建模，然後逐步完成。

注意：就我目前看到的功能而言，您並不熟悉Java中的面向對象編程。這就是爲什麼我沒有提供關於使用類的好處的原因。然而，如果你是，那麼請讓我知道，我會添加信息到我的文章。

祝你好運！

Answer 3

例如，你可以使用類似的東西：

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; 
    } 
} 

而另一個類來操作：

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."); 
    } 
} 

但你不應該拋出IllegalArgumentException，也有處理意外論點的另一個選擇。

Answer 4

因爲我不想讓你完全解決這個問題，而且你似乎對Java語言有一些瞭解，所以我只會寫下我將如何繼續/改變你的開始。

首先，我會將結果存儲在您的運算符if語句中。結果是一個int。

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

在此之後，我會打印數學問題並等待用戶回答。

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. 

在此階段，您所要做的就是將結果與用戶輸入進行比較並打印出消息。

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

該溶液是或多或少psudo代碼和一些錯誤處理（如果用戶輸入在答案例如測試）丟失，也我將其分解成方法，而不是擁有這一切在main（） 。下一步將是使它面向對象（看看demi的答案）。祝你好運，最終確定你的節目。

Answer 5

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();