为什么这个循环不能正常运行

Question

我想编写一个 java 程序，在其中询问用户他们想要回答多少数学问题，并使用任何选择循环根据他们的答案生成随机问题，并记录他们回答正确的数量。我得到它来生成随机数学问题，但它只在它似乎跳过循环时才这样做。任何人都可以帮忙吗？import javax.swing.JOptionPane;import java.util.Random;import java.util.Scanner;/** * * @author user */public class MathQuiz {    /**     * @param args the command line arguments     */    public static void main(String[] args) {        Scanner input = new Scanner(System.in);        Random obj = new Random();        int num1 = obj.nextInt(10);        int num2 = obj.nextInt(10);        int rand = num1 + num2;        String response = JOptionPane.showInputDialog(null,"How many problems would you like to solve?");        int ans = Integer.parseInt(response); // answer from question        String result= null;        int times = input.nextInt();        int counter = 0; //counts total math problems        while (counter != ans){            counter++;            JOptionPane.showInputDialog(num1 + "+" +num2);            if (ans == rand){                result= "Correct";            }else {                result= "Incorrect";            }        }   JOptionPane.showMessageDialog(null, );        }}  

Answer 1

您在循环中获得的数字不应与您在 while(...) 条件中使用的数字存储在同一变量中。在这种情况下，您使用了 ans。在下面的示例中，我为数学答案和循环中迭代的次数设置了单独的变量。您遇到的另一个问题是您没有将结果消息传递给 showMessageDialog(..) 方法。

import javax.swing.JOptionPane;

import java.util.Random;

import java.util.Scanner;

public class MathQuiz {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);

        Random obj = new Random();

        String timesString = JOptionPane.showInputDialog(null,"How many problems would you like to solve?");

        int timesInt = Integer.parseInt(timesString); // answer from question

        int counter = 0; //counts total math problems

        while (counter != timesInt) {

            counter++;

            int num1 = obj.nextInt(10);

            int num2 = obj.nextInt(10);

            int rand = num1 + num2;

            String answerString = JOptionPane.showInputDialog(num1 + "+" +num2);

            int answerInt = Integer.parseInt(answerString);

            JOptionPane.showMessageDialog(null, answerInt == rand ? "Correct" : "Incorrect");

        }

    }

}

Answer 2

以下是您的代码中的问题： 计算值后没有显示结果。不是每次都生成随机数。

    public class MathQuiz {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);

        String response = JOptionPane.showInputDialog(null,"How many problems would you like to solve?");

        int noOfTimes = Integer.parseInt(response); // answer from question

        String result= null;

        for (int counter = 0; counter < noOfTimes; counter++) {

            Random obj = new Random();

            int num1 = obj.nextInt(10);

            int num2 = obj.nextInt(10);

            int rand = num1 + num2;

            int answer = Integer.parseInt(JOptionPane.showInputDialog(num1 + "+" +num2));

            if (answer == rand){

                result= "Correct";

            }else {

                result= "Incorrect";

            }

            JOptionPane.showMessageDialog(null, result);

        }

    }

}